#include<iostream>
#include<vector>
#include<set>
using namespace std;
using P = pair<int,int>;

int main(){
	int N;cin>>N;
	set<P> s;
	bool ans = false;
	for(int i=0;i<N;++i){
		int a,b;cin>>a>>b;
		if(s.contains(P(a,b))){
			ans = true;
		}
		s.emplace(a,b);
	}

	cout << (ans ? "Yes" : "No") << endl;
	
}