#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000086, MOD = 1e9 + 7, INF = 0x3f3f3f3f;
ll res;
int n, m, cnt, w[N];




int main() {
	cin >> n;
	map<pii, int> ma;
	for (int i = 1; i < n + 1; i++) {
		int a, b;
		scanf("%d%d", &a, &b);
		ma[{a, b}]++;
	}
	for (auto u : ma)
		if (u.second > 1) {
			puts("Yes");
			return 0;
		}
	puts("No");
	return 0;
}