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#include <algorithm>
#include <cstdio>
#include <map>
#include <set>
#include <vector>
using namespace std;

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define FORD(i,a,b) for (int i = (b) - 1; i >= (a); --i)
#define REPD(i,n) FORD(i,0,n)
#define VAR(v,w) __typeof(w) v=(w)
#define FORE(it,c) for(VAR(it,(c).begin());it!=(c).end();++it)

struct L {
	int y, i;
};

struct T {
	int x1, x2, why1, y2, i;
	L bot() const {
		L l;
		l.y = why1;
		l.i = i;
		return l;
	}
};

bool bottomSort(const T& t1, const T& t2) {
	return t1.why1 > t2.why1;
}

bool lexSort(const T& t1, const T& t2) {
	if (t1.x1 != t2.x1) return t1.x1 < t2.x1;
	if (t1.x2 != t2.x2) return t1.x2 < t2.x2;
	if (t1.why1 != t2.why1) return t1.why1 < t2.why1;
	return t1.y2 < t2.y2;
}

bool operator<(const L& l1, const L& l2) {
	if (l1.y != l2.y) return l1.y < l2.y;
	return l1.i > l2.i;
}

struct Node {
	set<L> full, partial;
};

int n, x1[100000], x2[100000], why1[100000], y2[100000], bottom;
map<int, int> backX, backY;
vector<T> t, t2;
set<int> existing;
Node nodes[1 << 19];

void reshape(int* a, int* b, map<int, int>& back) {
	map<int, int> m;
	REP(i,n) m[a[i]] = m[b[i]] = -1;
	int ii = 0;
	FORE(it,m) {
		it->second = ii;
		back[ii] = it->first;
		++ii;
	}
	REP(i,n) {
		a[i] = m[a[i]];
		b[i] = m[b[i]];
	}
}

template <class V>
void visit(V& visitor, int x, int y, int i, int level) {
	int xx = (i - (1 << level)) << (bottom - level);
	int yy = (i - (1 << level) + 1) << (bottom - level);
	if (x == xx && y == yy) {
		visitor.final(nodes[i]);
		return;
	}
	int mid = (xx + yy) >> 1;
	if (x < mid) visit(visitor, x, min(y, mid), i << 1, level + 1);
	if (mid < y) visit(visitor, max(x, mid), y, (i << 1) | 1, level + 1);
	visitor.internal(nodes[i]);
}

template <class V>
void visit(V& visitor, int x, int y) {
	visit(visitor, x, y, 1, 0);
}

void join(const T& t1, const T& t2, T& t3) {
	t3.x1 = min(t1.x1, t2.x1);
	t3.x2 = max(t1.x2, t2.x2);
	t3.why1 = min(t1.why1, t2.why1);
	t3.y2 = max(t1.y2, t2.y2);
}

int findIn(const T& tt, const set<L> s) {
	set<L>::iterator it = s.begin();
	if (it == s.end()) return -1;
	if (it->y < tt.y2) return it->i;
	return -1;
}

struct AddVisitor {
	const T& tt;
	AddVisitor(const T& tt) : tt(tt) {}
	void internal(Node& node) {
		node.partial.insert(tt.bot());
	}
	void final(Node& node) {
		node.full.insert(tt.bot());
	}
};

struct RemoveVisitor {
	const T& tt;
	RemoveVisitor(const T& tt) : tt(tt) {}
	void internal(Node& node) {
		node.partial.erase(tt.bot());
	}
	void final(Node& node) {
		node.full.erase(tt.bot());
	}
};

struct FindVisitor {
	const T& tt;
	int found;
	FindVisitor(const T& tt) : tt(tt), found(-1) {}
	void internal(Node& node) {
		if (found >= 0) return;
		found = findIn(tt, node.full);
	}
	void final(Node& node) {
		if (found >= 0) return;
		found = findIn(tt, node.full);
		if (found < 0) found = findIn(tt, node.partial);
	}
};

void add(int i) {
	for (;;) {
		FindVisitor fv(t[i]);
		visit(fv, t[i].x1, t[i].x2);
		if (fv.found == -1) {
			AddVisitor av(t[i]);
			visit(av, t[i].x1, t[i].x2);
			existing.insert(i);
			break;
		}
		RemoveVisitor rv(t[fv.found]);
		visit(rv, t[fv.found].x1, t[fv.found].x2);
		existing.erase(fv.found);
		T tt;
		join(t[i], t[fv.found], tt);
		i = tt.i = t.size();
		t.push_back(tt);
	}
}

int main() {
	scanf("%d", &n);
	REP(i,n) scanf("%d%d%d%d", &x1[i], &x2[i], &why1[i], &y2[i]);
	reshape(x1, x2, backX);
	reshape(why1, y2, backY);
	int xx = 0;
	t.reserve(n);
	REP(i,n) {
		T tt;
		tt.x1 = x1[i];
		tt.x2 = x2[i];
		tt.why1 = why1[i];
		tt.y2 = y2[i];
		t.push_back(tt);
		xx = max(xx, x2[i]);
	}
	sort(t.begin(), t.end(), bottomSort);
	REP(i,n) t[i].i = i;
	while ((1 << bottom) < xx) ++bottom;
	REP(i,n) add(i);
	int m = existing.size();
	t2.reserve(m);
	FORE(it,existing) t2.push_back(t[*it]);
	sort(t2.begin(), t2.end(), lexSort);
	printf("%d\n", m);
	REP(i,m) printf("%d %d %d %d\n", backX[t2[i].x1], backX[t2[i].x2], backY[t2[i].why1], backY[t2[i].y2]);
}