#include <iostream>

using namespace std;

int main(){
  int n;
  cin >> n;
  bool is_exist[n];
  for (int i = 0; i < n; ++i) is_exist[i] = true;
  int a[n], b[n];
  for (int i = 0; i < n; ++i){
    cin >> a[i] >> b[i];
  }
  for (int i = 0; i < n-1; ++i)
  for (int j=i+1; j < n; ++j)
  if (a[i] > a[j]){
    int tmp = a[i]; a[i] = a[j]; a[j] = tmp;
    tmp = b[i]; b[i] = b[j]; b[j] = tmp;
  }
  int i = 0;
  while (i < n){
    if (is_exist[i]){
      for (int j = i+1; j < n; ++j){
        if (a[j] <= b[i] && is_exist[j]){
          if (b[i] < b[j]) b[i] = b[j];
          is_exist[j] = false;
        }
      }
    }
    ++i;
  }
  for (int i = 0; i < n; ++i){
    if (is_exist[i]){
      cout << a[i] << " " << b[i] << endl;
    }
  }
  return 0;
}