#include<bits/stdc++.h>
using namespace std;
struct student {
		int kai;
		int jie;
	
} p[50005];
bool cmp (student a ,student b){
	if(a.jie==b.jie){
	return a.kai<b.kai; 
	}else{
	return a.jie<b.jie;	
	}
}
int n;
int sum=1;
int jie1,kai1;
int main() {
	cin >> n;
	for(int i=1; i<=n; i++) {
		cin >> p[i].kai>>p[i].jie;
		
	}
	sort (p+1,p+n+1,cmp);
	kai1=1;
	jie1=p[1].jie;
	for(int i=2;i<=n;i++) {
		if(p[i].kai<=jie1&&p[i].jie>jie1){
			jie1=p[i].jie;
		}
		if(p[i].kai>jie1){
			cout<<kai1<<" "<<jie1<<endl;
			kai1=p[i].kai;
			jie1=p[i].jie;
		} 
	}
	cout<<kai1<<" "<<jie1<<endl;
	return 0;
}