#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define rep1(i, j, n) for (int i = (int)j; i < (int)n; i++)
using ll = long long int;

int main() {
  int n;
  cin >> n;
  set<int> m;
  rep(i, n) {
    int a, b;
    cin >> a >> b;
    m.insert(a*10000 + b);
  }
  if ((int)m.size() < n)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}