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#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <queue>
#include <ctime>
#include <map>
#include <cstdio>
#include <iomanip>
#include <sstream>
#include <iostream>
#include <cstring>
#define REP(i,x,v)for(int i=x;i<=v;i++)
#define REPD(i,x,v)for(int i=x;i>=v;i--)
#define FOR(i,v)for(int i=0;i<v;i++)
#define FORE(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define REMIN(x,y) (x)=min((x),(y))
#define REMAX(x,y) (x)=max((x),(y))
#define pb push_back
#define sz size()
#define mp make_pair
#define fi first
#define se second
#define ll long long
#define IN(x,y) ((y).find((x))!=(y).end())
#define un(v) v.erase(unique(ALL(v)),v.end())
#define LOLDBG
#ifdef LOLDBG
#define DBG(vari) cerr<<#vari<<" = "<<vari<<endl;
#define DBG2(v1,v2) cerr<<(v1)<<" - "<<(v2)<<endl;
#else
#define DBG(vari)
#define DBG2(v1,v2)
#endif
#define CZ(x) scanf("%d",&(x));
#define CZ2(x,y) scanf("%d%d",&(x),&(y));
#define CZ3(x,y,z) scanf("%d%d%d",&(x),&(y),&(z));
#define ALL(x) (x).begin(),(x).end()
#define tests int dsdsf;cin>>dsdsf;while(dsdsf--)
#define testss int dsdsf;CZ(dsdsf);while(dsdsf--)
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
template<typename T,typename TT> ostream &operator<<(ostream &s,pair<T,TT> t) {return s<<"("<<t.first<<","<<t.second<<")";}
template<typename T> ostream &operator<<(ostream &s,vector<T> t){s<<"{";FOR(i,t.size())s<<t[i]<<(i==t.size()-1?"":",");return s<<"}"<<endl; }
typedef pair<pii,pii> pr;

/////////////////////
////// INPUT ////////
////////////////////
typedef unsigned long long ull;
class INPUT {
static const int BUFSIZE = 1<<16;
static char buffer[];
char *bufpos;
char *bufend;
void grabBuffer();
public:
INPUT() { grabBuffer(); }
bool eof() { return bufend==buffer; }
char nextChar() { return *bufpos; }
inline char readChar();
inline void skipWS();
unsigned readUnsigned();
int readInt();
ull readULL();
};

char INPUT::buffer[INPUT::BUFSIZE];

void INPUT::grabBuffer() {
bufpos = buffer;
bufend = buffer + fread( buffer, 1,BUFSIZE,stdin);
}

char INPUT::readChar() {
char res = *bufpos++;
if(bufpos==bufend) grabBuffer();
return res;
}

inline bool myisspace(char c) { return c<=' '; }

void INPUT::skipWS() {
while(!eof() && myisspace(nextChar())) readChar();
}

unsigned INPUT::readUnsigned() {
skipWS();
unsigned res = 0;
while(!eof() && isdigit(nextChar())) {
res = 10u * res + (readChar()-'0');
}
return res;
}

ull INPUT::readULL() {
skipWS();
ull res = 0;
while(!eof() && isdigit(nextChar())) {
res = 10ULL * res + (readChar()-'0');
}
return res;
}

int INPUT::readInt() {
	skipWS();
	bool neg = false;
	if(!eof() && nextChar()=='-') { neg=true; readChar(); }
	int res = static_cast<int>(readUnsigned());
	if(neg) res = -res;
	return res;
}

/////////////////////
////// OUTPUT //////
////////////////////

class OUTPUT {
static const int BUFSIZE = 1<<16;
static char buffer[];
char *bufpos;
char *BUFLIMIT;
void flushBuffer();
public:
	OUTPUT():bufpos(buffer),BUFLIMIT(buffer+BUFSIZE-100) {}
	~OUTPUT() { flushBuffer(); }
	inline void operator()(char c);
	inline void operator()(unsigned x);
	inline void operator()(int x);
	inline void operator()(unsigned long long int x);
	inline void operator()(long long int x);
	inline void operator()(const char*s);
	void operator()(const string&s) { operator()(s.c_str()); }
	template<class A,class B>
	void operator()(const A& a,const B& b) {
		operator()(a); operator()(b);
	}
	template<class A,class B,class C>
	void operator()(const A& a,const B& b,const C&c) {
		operator()(a); operator()(b); operator()(c);
	}
	template<class A,class B,class C,class D>
	void operator()(const A& a,const B& b,const C&c,const D&d) {
		operator()(a); operator()(b); operator()(c); operator()(d);
	}
	template<class A,class B,class C,class D,class E>
	void operator()(const A& a,const B& b,const C&c,const D&d,const E&e) {
		operator()(a); operator()(b); operator()(c); operator()(d); operator()(e);
	}
	template<class A,class B,class C,class D,class E,class F>
	void operator()(const A& a,const B& b,const C&c,const D&d,const E&e,const F&f) {
		operator()(a); operator()(b); operator()(c); operator()(d); operator()(e); operator()(f);
	}
};

char OUTPUT::buffer[OUTPUT::BUFSIZE];

void OUTPUT::flushBuffer() {
	char *p = buffer;
	while(p < bufpos) {
		p += fwrite( p,1, bufpos-p,stdout);
	}
	bufpos = buffer;
}

void OUTPUT::operator()(char c) {
	*bufpos = c;
	++bufpos;
	if(bufpos >= BUFLIMIT) flushBuffer();
}

void OUTPUT::operator()(unsigned x) {
	char *old = bufpos;
	do {
		*bufpos = char('0' + x % 10u);
		x /= 10u;
		++bufpos;
	} while(x);
	reverse(old, bufpos);
	if(bufpos >= BUFLIMIT) flushBuffer();
}

void OUTPUT::operator()(int x) {
	if(x<0) { operator()('-'); x = -x; }
	operator()(static_cast<unsigned>(x));
}

void OUTPUT::operator()(unsigned long long int x) {
	char *old = bufpos;
	do {
		*bufpos = char('0' + x % 10u);
		x /= 10u;
		++bufpos;
	} while(x);
	reverse(old, bufpos);
	if(bufpos >= BUFLIMIT) flushBuffer();
}

void OUTPUT::operator()(long long int x) {
	if(x<0) { operator()('-'); x = -x; }
	operator()(static_cast<unsigned long long int>(x));
}

void OUTPUT::operator()(const char*s) {
	while(*s) operator()(*s++);
}

INPUT input;
OUTPUT output;

#define INF (1<<25)
pr p[111111];
int n;

pr b[111111];

pr przekroj(pr A,pr B)
{
    pr W;
    W.fi.fi=max(A.fi.fi,B.fi.fi);
    W.fi.se=min(A.fi.se,B.fi.se);
    W.se.fi=max(A.se.fi,B.se.fi);
    W.se.se=min(A.se.se,B.se.se);
    return W;
}

pr suma(pr A,pr B)
{
    pr W;
    W.fi.fi=min(A.fi.fi,B.fi.fi);
    W.fi.se=max(A.fi.se,B.fi.se);
    W.se.fi=min(A.se.fi,B.se.fi);
    W.se.se=max(A.se.se,B.se.se);
    return W;
}

bool nonempty(pr A)
{
	return (A.fi.fi<A.fi.se && A.se.fi<A.se.se);
}

bool nalezy(pii X, pr A)
{
	return (A.fi.fi<=X.fi && X.fi<=A.fi.se && A.se.fi<=X.se && X.se<=A.se.se);
}

bool rog_nalezy(pr A, pr B)
{
    if (nalezy(mp(A.fi.fi,A.se.fi),B)) return 1;
    if (nalezy(mp(A.fi.se,A.se.fi),B)) return 1;
    if (nalezy(mp(A.fi.fi,A.se.se),B)) return 1;
    if (nalezy(mp(A.fi.se,A.se.se),B)) return 1;
    return 0;
}

pr losuj(int R=5)
{
    int a=0,b=0;
    while(a>=b){a=rand()%R;b=rand()%R;}
    int c=0,d=0;
    while(c>=d){c=rand()%R;d=rand()%R;}
    return mp(mp(a,b),mp(c,d));
}

void gen_test(int N,int R)
{
	n=N;
    FOR(i,n) p[i+1]=losuj(R);
}

vector<pr> brut()
{
    FOR(i,n) b[i]=p[i+1];
    int N=n;
    while(1)
	{
		bool zmiana=0;
		FOR(i,N)FOR(j,i)
		{
			pr w=przekroj(b[i],b[j]);
			if (w.fi.fi<w.fi.se && w.se.fi<w.se.se)
			{
				zmiana=1;
                b[j]=suma(b[i],b[j]);
                swap(b[i],b[N-1]);
                N--;
                break;
			}
		}
		if (!zmiana) break;
	}
	sort(b,b+N);
	return vector<pr>(b,b+N);

}

pr K[111111];
vi X,Y;
int lx,ly;
set<pii> ev;
set<pii> miotla;

int fu[111111];

int szuk(int x)
{
	if (fu[x]==x) return x;
	return fu[x]=szuk(fu[x]);
}

int unia(int x,int y)
{
	x=szuk(x);
	y=szuk(y);
	if (x!=y)
	{
        fu[y]=x;
        K[x]=suma(K[x],K[y]);
	}
	return x;
}

int getX(int x){return lower_bound(ALL(X),x)-X.begin();}
int getY(int x){return lower_bound(ALL(Y),x)-Y.begin();}

void wywal_z_miotly(int nr)
{
	miotla.erase(mp(K[nr].se.fi,-nr));
	miotla.erase(mp(K[nr].se.se,nr));
}

int polacz(int x,int y)
{
    wywal_z_miotly(x);
    wywal_z_miotly(y);
    x=unia(x,y);
    return x;
}

vector<pr> sol2()
{
	X.clear();
	Y.clear();
    REP(i,1,n)
    {
    	X.pb(p[i].fi.fi);X.pb(p[i].fi.se);
    	Y.pb(p[i].se.fi);Y.pb(p[i].se.se);
    }
    sort(ALL(X));un(X);
    sort(ALL(Y));un(Y);
    REP(i,1,n)
    {
        K[i].fi.fi=getX(p[i].fi.fi);
        K[i].fi.se=getX(p[i].fi.se)-1;
        K[i].se.fi=getY(p[i].se.fi);
        K[i].se.se=getY(p[i].se.se)-1;
    }
    //DBG(vector<pr>(K+1,K+n+1));
    lx=X.sz;
    ly=Y.sz;
    REP(i,1,n) fu[i]=i;
    FOR(jj,n)
    {

    ev.clear();
    miotla.clear();
    REP(i,1,n)
    {
    	if (szuk(i)==i)
        ev.insert(mp(K[i].fi.fi,-i));
    }
    set<pii>::iterator it1,it2;
	//DBG(vector<pr>(K+1,K+n+1));
	//DBG(vi(fu+1,fu+n+1));
    while(ev.sz)
	{
        pii u=*(ev.begin());ev.erase(ev.begin());
        //DBG(u);
        int nr=abs(u.se);
        if (u.se>0)
		{
            nr=szuk(nr);
            //DBG(nr);
            if (K[nr].fi.se==u.fi)
			{
				wywal_z_miotly(nr);

			}
		}
		else
		{
            while(1)
			{
                it1=miotla.insert(mp(K[nr].se.fi,-nr)).fi;
                it2=miotla.insert(mp(K[nr].se.se,nr)).fi;
                it1++;
                //DBG(*it1);
                if (*it1!=*it2)
				{
                    int nr2=abs(it1->se);
                    nr=polacz(nr,nr2);
                    continue;
				}
                it2++;
                if (it2==miotla.end() || it2->se<0) break;
                int nr2=abs(it2->se);
                nr=polacz(nr,nr2);
				continue;
			}
            ev.insert(mp(K[nr].fi.se,nr));
		}
		//DBG(u);
	}
    REP(i,1,n) fu[i]=szuk(i);
    }

    //DBG(vi(fu+1,fu+n+1));
    vector<pr> wyn;
    REP(i,1,n)
    {
    	if (szuk(i)==i)
		{
            pr f=K[i];
            f.fi.fi=X[f.fi.fi];
            f.fi.se=X[f.fi.se+1];
            f.se.fi=Y[f.se.fi];
            f.se.se=Y[f.se.se+1];
            wyn.pb(f);
		}
    }
    sort(ALL(wyn));
    return wyn;
}


int M;

set<pii> d[1<<19];

void dod(int a,pii val)
{
    a+=M;
    while(a)
    {
        d[a].insert(mp(-val.fi,val.se));
        a/=2;
    }
}

void usu(int a,pii val)
{
    a+=M;
    while(a)
    {
        d[a].erase(mp(-val.fi,val.se));
        a/=2;
    }
}

int A,B,C;

pii sum(int l,int r,int nr)
{
    if (l>B || r<A) return mp(INF,0);
    if (A<=l && r<=B)
	{
        set<pii>::iterator it=d[nr].lower_bound(mp(-C,-INF));
        if (it==d[nr].end()) return mp(INF,0);
        return *it;
	}
    pii p1=sum(l,(l+r)/2,nr*2);
    pii p2=sum((l+r)/2+1,r,nr*2+1);
    return (p1<p2?p1:p2);
}

pii query(int a,int b,int c)//[a,b]x[-inf,c]
{
    int wyn=0;
    C=c;
    A=a;
    B=b;
    pii pp=sum(0,M-1,1);
    return mp(-pp.fi,pp.se);
}



set<pair<pii,int> > rogi;



void wyczysc_rog(int nr)
{
    //rogi.erase(mp(mp(K[nr].fi.fi,K[nr].se.fi),nr));
    //rogi.erase(mp(mp(K[nr].fi.se,K[nr].se.fi),nr));
    //rogi.erase(mp(mp(K[nr].fi.fi,K[nr].se.se),nr));
    //rogi.erase(mp(mp(K[nr].fi.se,K[nr].se.se),nr));
    usu(K[nr].fi.fi,mp(K[nr].se.fi,nr));
    usu(K[nr].fi.se,mp(K[nr].se.fi,nr));
    usu(K[nr].fi.fi,mp(K[nr].se.se,nr));
    usu(K[nr].fi.se,mp(K[nr].se.se,nr));
}

void dodaj_rog(int nr)
{
    //rogi.insert(mp(mp(K[nr].fi.fi,K[nr].se.fi),nr));
    //rogi.insert(mp(mp(K[nr].fi.se,K[nr].se.fi),nr));
    //rogi.insert(mp(mp(K[nr].fi.fi,K[nr].se.se),nr));
    //rogi.insert(mp(mp(K[nr].fi.se,K[nr].se.se),nr));
    dod(K[nr].fi.fi,mp(K[nr].se.fi,nr));
    dod(K[nr].fi.se,mp(K[nr].se.fi,nr));
    dod(K[nr].fi.fi,mp(K[nr].se.se,nr));
    dod(K[nr].fi.se,mp(K[nr].se.se,nr));
}



vector<pr> sol()
{
	X.clear();
	Y.clear();
    REP(i,1,n)
    {
    	X.pb(p[i].fi.fi);X.pb(p[i].fi.se);
    	Y.pb(p[i].se.fi);Y.pb(p[i].se.se);
    }
    sort(ALL(X));un(X);
    sort(ALL(Y));un(Y);
    M=1;
    while(M<=X.sz+2) M*=2;
    FOR(i,2*M)d[i].clear();
    REP(i,1,n)
    {
        K[i].fi.fi=getX(p[i].fi.fi);
        K[i].fi.se=getX(p[i].fi.se)-1;
        K[i].se.fi=getY(p[i].se.fi);
        K[i].se.se=getY(p[i].se.se)-1;
    }
    //DBG(vector<pr>(K+1,K+n+1));
    lx=X.sz;
    ly=Y.sz;
    REP(i,1,n) fu[i]=i;

    ev.clear();
    miotla.clear();
    REP(i,1,n)
    {
    	if (szuk(i)==i)
        ev.insert(mp(K[i].fi.fi,-i));
    }
    set<pii>::iterator it1,it2;
	//DBG(vector<pr>(K+1,K+n+1));
	//DBG(vi(fu+1,fu+n+1));
    while(ev.sz)
	{
        pii u=*(ev.begin());ev.erase(ev.begin());
        //DBG(u);
        int nr=abs(u.se);
        if (u.se>0)
		{
            nr=szuk(nr);
            //DBG(nr);
            if (K[nr].fi.se==u.fi)
			{
				wywal_z_miotly(nr);

			}
		}
		else
		{
            while(1)
			{
                it1=miotla.insert(mp(K[nr].se.fi,-nr)).fi;
                it2=miotla.insert(mp(K[nr].se.se,nr)).fi;
                it1++;
                //DBG(*it1);
                if (*it1!=*it2)
				{
                    int nr2=abs(it1->se);
                    nr=polacz(nr,nr2);
                    continue;
				}
                it2++;
                if (it2==miotla.end() || it2->se<0) break;
                int nr2=abs(it2->se);
                nr=polacz(nr,nr2);
				continue;
			}
            ev.insert(mp(K[nr].fi.se,nr));
		}
		//DBG(u);
	}
	set<pair<pii,int > >::iterator it;
    rogi.clear();
    REP(i,1,n) if (i==szuk(i)) dodaj_rog(i);
    REP(i,1,n)
    {
		{
			int nr=szuk(i);
			if (i>1 && nr==szuk(i-1)) continue;
			wyczysc_rog(nr);
			bool zmiana=1;
			while(zmiana)
			{
				zmiana=0;
				pii u=query(K[nr].fi.fi,K[nr].fi.se,K[nr].se.se);
				if (u.fi>=K[nr].se.fi)
				{
					zmiana=1;
					wyczysc_rog(u.se);
					nr=unia(nr,u.se);
				}
				/*for(it=rogi.begin();it!=rogi.end();it++)
				{
					pii u=it->fi;
					if (K[nr].fi.fi<=u.fi && u.fi<=K[nr].fi.se && K[nr].se.fi<=u.se && u.se<=K[nr].se.se)
					{
						zmiana=1;
						//DBG(*it);
						wyczysc_rog(it->se);
						nr=unia(nr,it->se);
						//DBG(nr);
						break;
					}
				}*/
				//DBG(zmiana);
			}
			dodaj_rog(nr);
		}
    }

    /*REP(i,1,n)REP(j,1,i-1)
    {
    	if (szuk(i)==i && szuk(j)==j)
		{
			pr prz=przekroj(K[i],K[j]);
			if (prz==K[i] || prz==K[j]) unia(i,j);
		}
    }*/

    //DBG(vi(fu+1,fu+n+1));
    vector<pr> wyn;
    REP(i,1,n)
    {
    	if (szuk(i)==i)
		{
            pr f=K[i];
            f.fi.fi=X[f.fi.fi];
            f.fi.se=X[f.fi.se+1];
            f.se.fi=Y[f.se.fi];
            f.se.se=Y[f.se.se+1];
            wyn.pb(f);
		}
    }
    sort(ALL(wyn));
    return wyn;
}


int main2()
{
	//srand(time(0));
	int cnt=0;
	while(1)
	{
		cnt++;
		if (cnt%100==0) DBG(cnt);
		int N=1+rand()%20;
		int R=2+rand()%30;
		gen_test(N,R);
		if (brut()!=sol())
		{
			DBG(vector<pr>(p+1,p+n+1));
			DBG(brut());
			DBG(sol());
			return 0;
		}
	}
    return 0;
}

int main22()
{
	//srand(time(0));
	n=80000;
	REP(i,1,n)
	{
        p[i].fi.fi=rand();
        p[i].fi.se=p[i].fi.fi+2;
        p[i].se.fi=rand();
        p[i].se.se=p[i].se.fi+2;
	}
	//DBG(sol());
	vector<pr> v=sol();
	DBG(v.sz);
	//printf("%d\n",v.sz);
	//FOR(i,v.sz) printf("%d %d %d %d\n",v[i].fi.fi,v[i].fi.se,v[i].se.fi,v[i].se.se);
    return 0;
}


int main()
{
	n=input.readInt();
	REP(i,1,n)
	{
		p[i].fi.fi=input.readInt();
		p[i].fi.se=input.readInt();
        p[i].se.fi=input.readInt();
        p[i].se.se=input.readInt();
	}
	//DBG(sol());
	vector<pr> v=sol();
	//printf("%d\n",v.sz);
	output(v.sz,"\n");
	FOR(i,v.sz)
	{
		output(v[i].fi.fi," ",v[i].fi.se);
		output(" ",v[i].se.fi," ",v[i].se.se,"\n");
		//printf("%d %d %d %d\n",v[i].fi.fi,v[i].fi.se,v[i].se.fi,v[i].se.se);
	}

    return 0;
}