#include <iostream>
#include <sstream>
#include <iomanip>
#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];


  for (int i = 0; i < n; i++) {
    ostringstream oss1, oss2;
    oss1 << setw(5) << setfill('0') << a[i][0];
    oss2 << setw(5) << setfill('0') << a[i][1];
    string s1 = oss1.str();
    string s2 = oss2.str();
    s[i] = s1 + s2;
  }

  sort(s, s+n);
  bool flg = false;

  for (int i = 0; i < n; i++) {
    if (s[i] == s[i+1]) {
      flg = true;
      break;
    }
  }

  if (flg) {
    cout << "Yes" << endl;
  }else {
    cout << "No" << endl;
  }
}