#include <bits/stdc++.h>
//#include <atcoder/modint>

using namespace std;
//using namespace atcoder;
using ll = long long;
//using mint = modint998244353;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    int N;
    cin >> N;
    set<pair<int, int>> st;
    for (int i=0; i<N; i++){
        int a, b;
        cin >> a >> b;
        if (st.count({a, b})){
            cout << "Yes" << endl;
            return 0;
        }
        st.insert({a, b});
    }
    cout << "No" << endl;

    return 0;
}