#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
  int n;
  cin >> n;
  int a[n][2];
  string s[n];

  for(int i = 0; i < n; i++) cin >> a[i][0] >> a[i][1];
  int cnt = 0;

  bool found = false;
  for (int i = 0; i < n && !found; ++i) {
    for (int l = 0; l < n; ++l) {
      if (l != i && a[i][0] == a[l][0] && a[i][1] == a[l][1]) {
        ++cnt;
        found = true;
        break;
      }
    }
  }

  if(cnt >= 1){
    cout << "Yes" << endl;
  }else{
    cout << "No" << endl;
  }





}