Beyond the Void

/* 
 * Problem: POI2001 prz
 * Author: Guo Jiabao
 * Time: 2009.1.6 21:37
 * State: Solved 
*/
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
 
using namespace std;
 
const int MAX=50001;
 
struct Interval
{
	int p;
	bool s;
};
 
int N;
Interval A[MAX*2];
 
int cmp (const void *a, const void *b)
{
	if ( ((Interval *)a)->p < ((Interval *)b)->p ) return -1;
	else if ( ((Interval *)a)->p > ((Interval *)b)->p ) return 1;
	else if ( ((Interval *)a)->s ) return -1;
	return 1;
}
 
void init()
{
	int i;
	freopen("prz.in","r",stdin);
	freopen("prz.out","w",stdout);
	scanf("%d",&N);
	for (i=1;i<=N;i++)
	{
		scanf("%d%d",&A[i*2-1].p,&A[i*2].p);
		A[i*2-1].s=true;
		A[i*2].s=false;
	}
	N*=2;
	qsort(A+1,N,sizeof(A[0]),cmp);
}
 
void solve()
{
	int i,L,Level=0;
	for (i=1;i<=N;i++)
	{
		if (A[i].s)
		{
			Level++;
			if (Level==1)
				L=A[i].p;
		}
		else
		{
			Level--;
			if (Level==0)
				printf("%d %dn",L,A[i].p);
		}
	}
}
 
int main()
{
	init();
	solve();
	return 0;
}