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

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