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

using ll = long long;

vector<tuple<ll,ll,ll,ll>> APBQ;
vector<map<ll,ll>> memo;

ll N;
set<pair<ll,ll>> AB;
int main(){
    cin >> N;
    for (int i=0; i < N; i++){
        pair<ll,ll> ab;
        cin >> ab.first >> ab.second;
        if (AB.count(ab)){
            cout << "Yes" << endl;
            return 0;
        }
        AB.insert(ab);
    }
    cout << "No" << endl;
}