#include<bits/stdc++.h>
using namespace std;
int main() {
	int N;
	cin >> N;
  vector<pair<int, int>> A;
  for(int i = 0; i < N; i++){
    int a,b;
    cin >> a >> b;
    A.push_back({ a,b });
  }
  sort(A.begin(), A.end());
  for(int i = 0; i < N-1; i++){
    if(A.at(i) == A.at(i+1)){
      cout << "Yes" << endl;
      return 0;
    }
  }
  cout << "No" << endl;
  return 0;
}