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#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <list>
#include <ctime>
#include <sstream>
#include <queue>
#include <stack>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
using namespace std;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef long long ll;
typedef short int sint;
#define FOR(x, b, e) for(int x=(b); x<=(e); ++x)
#define FORD(x, b, e) for(int x=((int)(b))-1; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define VAR(v,n) typeof(n) v=(n)
#define ALL(c) c.begin(),c.end()
#define SIZE(x) ((int)((x).size()))
#define FOREACH(i,c) for(VAR(i,(c).begin());i!=(c).end();++i)
#define PB push_back
#define ST first
#define ND second
#define mp(x,y) make_pair(x,y)
#define DEBUG 1
#define debug(x) {if (DEBUG)cerr <<#x <<" = " <<x <<endl; }
#define debugv(x) {if (DEBUG) {cerr <<#x <<" = "; FOREACH(it, (x)) cerr <<*it <<", "; cout <<endl; }}
#define REMAX(a,b) (a)=max((a),(b));
#define REMIN(a,b) (a)=min((a),(b));
#define wez(n) int (n); scanf("%d",&(n));
#define wez2(n,m) int (n),(m); scanf("%d %d",&(n),&(m));

typedef pair<pii, pii> Pros;

const int N = 101000;
const int K = 1 << 19;
const int INF = 10001010;
Pros inp[N];
set<Pros> tabs;
int cnt[N];
int n;

inline Pros lacz(const Pros& p1, const Pros& p2) {
	return mp(
		mp(min(p1.ST.ST, p2.ST.ST), max(p1.ST.ND, p2.ST.ND)),
		mp(min(p1.ND.ST, p2.ND.ST), max(p1.ND.ND, p2.ND.ND))
	);
}

struct Wyd {
	int kt; bool ot;
	Wyd() {	}
	Wyd(int kt_, bool ot_): kt(kt_), ot(ot_) {
	}
	inline int getTime() const {
		if (ot) return inp[kt].ST.ST;
		else return inp[kt].ST.ND;
	}

	inline bool operator<(const Wyd& a) const {
		int t1 = getTime(), t2 = a.getTime();
		if (t1 != t2) {
			return t1 < t2;
		}
		if (ot != a.ot) {
			return ot > a.ot;
		}
		return inp[kt].ND < inp[a.kt].ND;
	}
};
Wyd kol[2 * N];

inline void zlacz(const int& dest, const int& source) {
	cnt[dest] += cnt[source];
	cnt[source] = 0;
	REMIN(inp[dest].ST.ST, inp[source].ST.ST);
	REMAX(inp[dest].ST.ND, inp[source].ST.ND);
	REMIN(inp[dest].ND.ST, inp[source].ND.ST);
	REMAX(inp[dest].ND.ND, inp[source].ND.ND);
}

int xx[2 * N], yy[2 * N];
map<int, int> mapX, mapY;

set<pii> drzewo[K];
set<pii> wspolne[K];
int P;

void dodaj(bool op, const pii& x, int x1, int x2, int pocz = 1, int kon = P, int ind = 1) {
	if (op) wspolne[ind].insert(x);
	else wspolne[ind].erase(wspolne[ind].find(x));
	int sr = (pocz + kon) / 2;
	if (x1 == pocz && x2 == kon) {
		if (op) drzewo[ind].insert(x);
		else drzewo[ind].erase(drzewo[ind].find(x));
	}
	else if (x2 <= sr) dodaj(op, x, x1, x2, pocz, sr, 2*ind);
	else if (x1 > sr) dodaj(op, x, x1, x2, sr+1, kon, 2*ind+1);
	else {
		dodaj(op, x, x1, sr, pocz, sr, 2*ind);
		dodaj(op, x, sr+1, x2, sr+1, kon, 2*ind+1);
	}
}

const pii BRAK = mp(-1, -1);

pii findElem(const set<pii>& zbior, const pii& range) {
	auto p = zbior.lower_bound(mp(range.ST, 0));
	if (p != zbior.end()) {
		if (p->ST <= range.ND) return *p;
	}
	return BRAK;
}

pii getFromRange(int x1, int x2, const pii& range, int pocz = 1, int kon = P, int ind = 1) {
	if (wspolne[ind].empty()) return BRAK;
	int sr = (pocz + kon) / 2;
	auto x = findElem(drzewo[ind], range);
	if (x != BRAK) return x;
	if (x1 == pocz && x2 == kon) {
		return findElem(wspolne[ind], range);
	} else if (x2 <= sr) {
		return getFromRange(x1, x2, range, pocz, sr, 2 * ind);
	} else if (x1 > sr) {
		return getFromRange(x1, x2, range, sr+1, kon, 2 * ind + 1);
	} else {
		x = getFromRange(x1, sr, range, pocz, sr, 2 * ind);
		if (x != BRAK) return x;
		return getFromRange(sr+1, x2, range, sr+1, kon, 2 * ind + 1);
	}
}

inline bool onLeft(const pii& a, const pii& b) {
	return a.ND < b.ST;
}

inline bool emptyCross(const pii& a, const pii& b) {
	return onLeft(a,b) || onLeft(b, a);
}

int main() {
	scanf("%d", &n);
	REP(i, n) {
		scanf("%d %d %d %d", &inp[i].ST.ST, &inp[i].ST.ND, &inp[i].ND.ST, &inp[i].ND.ND);
		--inp[i].ST.ND; --inp[i].ND.ND;
		xx[2 * i] = inp[i].ST.ST; xx[2 * i + 1] = inp[i].ST.ND;
		yy[2 * i] = inp[i].ND.ST; yy[2 * i + 1] = inp[i].ND.ND;
		kol[2 * i] = Wyd(i, 0);
		kol[2 * i + 1] = Wyd(i, 1);
		cnt[i] = 1;
	}
	sort(xx, xx + 2 * n); sort(yy, yy + 2 * n);
	int dx = unique(xx, xx + 2* n) - xx, dy = unique(yy, yy + 2 * n) - yy;
	REP(i, dx) {
		mapX[xx[i]] = i + 1;
	}
	REP(i, dy) {
		mapY[yy[i]] = i + 1;
	}
	REP(i, n) {
		inp[i].ST.ST = mapX[inp[i].ST.ST]; inp[i].ST.ND = mapX[inp[i].ST.ND];
		inp[i].ND.ST = mapY[inp[i].ND.ST]; inp[i].ND.ND = mapY[inp[i].ND.ND];
	}
	sort(kol, kol + 2 * n);
	P = 1;
	while (P < dx) {
		P <<= 1;
	}
	set<pii> zb;
	REP(i, 2 * n) {
		int x = kol[i].kt;
		if (kol[i].ot) {
			while (!zb.empty()) {
				pii szuk = mp(inp[x].ND.ST, -1);
				auto it = zb.lower_bound(szuk);
				if (it == zb.end() || inp[x].ND.ND < inp[it->ND].ND.ST) break;
				pii p = *it;

				// przeciecie z punktem: number p.ND, inp[p.ND].ND.ST oraz inp[p.ND].ND.ND
				zb.erase(zb.find(p));
				zlacz(x, p.ND);
				while (true) {
					p = getFromRange(inp[x].ST.ST, inp[x].ST.ND, inp[x].ND);
					if (p == BRAK) break ;
					zlacz(x, p.ND);
					dodaj(false /* delete */, p, inp[p.ND].ST.ST, inp[p.ND].ST.ND);
				}
			}
			zb.insert(mp(inp[x].ND.ST, x));
			zb.insert(mp(inp[x].ND.ND, x));
		} else {
			pii szuk = mp(inp[x].ND.ST, INF);
			auto p = zb.lower_bound(szuk);
			--p;
			if (cnt[p->ND] == 0) continue ;
			--cnt[p->ND];
			if (cnt[p->ND] == 0) {
				dodaj(true, *p, inp[p->ND].ST.ST, inp[p->ND].ST.ND);
				auto pop = p;
				if (inp[p->ND].ND.ST != inp[p->ND].ND.ND) {
					++pop;
					if (pop->ND == p->ND) {
						dodaj(true, *pop, inp[pop->ND].ST.ST, inp[pop->ND].ST.ND);
						zb.erase(pop);
					}
				}
				zb.erase(p);
			}
		}
	}
	for (const auto& vert : wspolne[1]) {
		tabs.insert(inp[vert.ND]);
	}
	printf("%d\n", SIZE(tabs));
	for (const auto& pros : tabs) {
		printf("%d %d %d %d\n", xx[pros.ST.ST - 1], xx[pros.ST.ND - 1]+1, yy[pros.ND.ST - 1], yy[pros.ND.ND - 1]+1);
	}
	return 0;
}