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#include<algorithm>
#include<bitset>
#include<cassert>
#include<complex>
#include<cstring>
#include<cstdio>
#include<iomanip>
#include<map>
#include<iostream>
#include<queue>
#include<set>
#include<stack>
#include<string>
#include<vector>

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORD(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i,n) for(int i=0; i<(n); ++i)
#define VAR(v,i) __typeof(i) v = (i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
#define PB push_back
#define MP make_pair
#define X first
#define Y second
#define debug(x) { cerr << #x <<" = " << (x) << endl; }
#define debugv(x) { cerr << #x << " = "; FORE(it, x) cerr << *it << ", "; cerr << endl;  }
#define dprintf(...) fprintf(stderr, __VA_ARGS__)

using namespace std;

typedef pair<int, int> PII;;
typedef vector<int> VI;
typedef long long LL;
typedef long double LD;
template<class C> void mini(C&a4, C b4) { a4 = min(a4,b4); }
template<class C> void maxi(C&a4, C b4) { a4 = max(a4,b4); }
template<class T1, class T2> ostream& operator<<(ostream &out, pair<T1, T2> pair) { return out << "(" << pair.X << ", "<< pair.Y << ")"; };

struct Rect {
    int x1, x2, y1, y2;
    bool is;

    bool operator<(const Rect& b) const {
        return y2 < b.y2;
    }
};

const int N = 1e5+1;
const int S = 1<<20;
int n;
Rect r[N];

struct V {
    PII top;
    PII back;
    vector< PII > que;
};
V t[S*2];

void update(int p) {
    while (!t[p].que.empty() && !r[t[p].que.back().Y].is) {
        t[p].que.pop_back();
    }

    if (t[p].que.empty()) { t[p].back = MP(-1, -1); }
    else { t[p].back = t[p].que.back(); }

    t[p].top = t[p].back;
    if (p < S) {
        maxi(t[p].top, t[p*2].top);
        maxi(t[p].top, t[p*2+1].top);
    }
}

PII query(int p, int a, int b, int A, int B) {
    if ((b <= A) || (B <= a)) return MP(-1,-1);
    if ((a <= A) && (B <= b)) return t[p].top;
    return max(
            max(query(p*2, a, b, A, (A+B)/2),
                query(p*2+1, a, b, (A+B)/2, B)),
            t[p].back);;
}

PII query(int x1, int x2) {
    return query(1, x1, x2, 0, S); 
}

void insert(int p, int a, int b, int A, int B, PII v) {
    if ((b <= A) || (B <= a)) return;
    if ((a <= A) && (B <= b)) {
        t[p].que.PB(v);
        update(p);
        return;
    }

    insert(p*2, a, b, A, (A+B)/2, v);
    insert(p*2+1, a, b, (A+B)/2, B, v);
    update(p);
}

void insert(int x1, int x2, PII v) {
    insert(1, x1, x2, 0, S, v);
}

void remove(int p, int a, int b, int A, int B) {
    if ((b <= A) || (B <= a)) return;
    if ((a <= A) && (B <= b)) {
        update(p);
        return;
    }

    remove(p*2, a, b, A, (A+B)/2);
    remove(p*2+1, a, b, (A+B)/2, B);
    update(p);
}

void remove(int x1, int x2) {
    remove(1, x1, x2, 0, S);
}

int main() {
    ios_base::sync_with_stdio();
    cout << fixed << setprecision(10);
    
    scanf("%d", &n);
    REP(i, n) {
        scanf("%d %d %d %d", &r[i].x1, &r[i].x2, &r[i].y1, &r[i].y2);
        r[i].is = true;
    }
    sort(r, r+n);

    REP(i, S*2) {
        t[i].top = MP(-1, -1);
        t[i].back = MP(-1, -1);
    }
    t[0].top = MP(0,0);

    REP(i, n) {
//        printf("%d!\n", i);
        do {
/*
            REP(i, S*2) {
                printf("(%d,%d) ", t[i].top.X, t[i].top.Y);
            }
            printf("\n");
            REP(i, S*2) {
                printf("(%d,%d) ", t[i].back.X, t[i].back.Y);
            }
            printf("\n");
*/
            PII res = query(r[i].x1, r[i].x2);

//            printf("query %d %d -> %d %d ? %d\n", r[i].x1, r[i].x2, res.X, res.Y, r[i].y1);
            if ((res.Y != -1) && (res.X > r[i].y1)) {
                int j = res.Y;
                mini(r[i].x1, r[j].x1);
                maxi(r[i].x2, r[j].x2);
                mini(r[i].y1, r[j].y1);
                maxi(r[i].y2, r[j].y2);
                
                r[j].is = false;
                remove(r[j].x1, r[j].x2);
            } else {
                break;
            }
        } while (true);
//        printf("Wrzucam %d %d -> %d %d\n", r[i].x1, r[i].x2, r[i].y2, i);
        insert(r[i].x1, r[i].x2, MP(r[i].y2, i));
    }
/*            
    REP(i, S*2) {
        printf("(%d,%d) ", t[i].top.X, t[i].top.Y);
    }
    printf("\n");
    REP(i, S*2) {
        printf("(%d,%d) ", t[i].back.X, t[i].back.Y);
    }
    printf("\n");
*/
    vector< pair<PII, PII> > res;
    REP(i, n) if (r[i].is) {
        res.PB(MP(MP(r[i].x1, r[i].x2), MP(r[i].y1, r[i].y2)));
    }
    sort(ALL(res));
    printf("%d\n", SZ(res));
    for (auto p: res) {
        printf("%d %d %d %d\n", p.X.X, p.X.Y, p.Y.X, p.Y.Y);
    }

    return 0;
}