#include<iostream>
#include<stdio.h>
using namespace std;
int vis[1000005];
int main()
{
	int n;
	cin >> n;
	while (n--){
		int a, b;
		scanf("%d%d", &a, &b);
		if (vis[a] < b)vis[a] = b;
	}
	for (int i = 1; i < 1000005; i++){
		if (vis[i]) {
			printf("%d ", i);
			int k = vis[i];
			for (int j = i + 1; j <= k; j++)
				if (vis[j] > k)k = vis[j];
			printf("%d\n", k);
			i = k;
		}
	}
	return 0;
}