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


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

	ll N;
	cin>>N;
	set<ll> S;
	for(int i=0;i<N;i++){
		ll A,B;
		cin>>A>>B;
		if(S.count(A*10000+B)){
			cout<<"Yes"<<endl;
			return 0;
		}
		S.insert(A*10000+B);
	}
	cout<<"No"<<endl;
	
}