#include <bits/stdc++.h>

using namespace std;

using pii = pair<int, int>;
using ll = long long;
const int N = 2000010, MOD = 1e9 + 7, INF = 0x3f3f3f3f;
int n, m, w[N];


void solve() {
	map<int, set<int> > ma;
	scanf("%d", &n);
	while (n--) {
		int x, y;
		scanf("%d%d", &x, &y);
		ma[x].insert(y);
	}
	for (auto& [x, u] : ma) {
		if (u.size() > 1) {
			puts("No");
			return;
		}
	}
	puts("Yes");
}

int main() {
	int T = 1;
	// scanf("%d", &T);
	while (T--) solve();
	return 0;
}