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

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

    int N; cin >> N;
    set<pair<int,int>> AB;
    while(N--){
        int a,b; cin >> a >> b;
        if(AB.count({a,b})){cout << "Yes\n"; return 0;}
        AB.insert({a,b});
    }
    cout << "No\n";
}