#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;

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