#include <bits/stdc++.h>
using namespace std;
#define N 100
int a[N], b[N];
int main() {
	int n;
	scanf("%d", &n);
	for(int i = 1; i <= n; i ++) scanf("%d%d", &a[i], &b[i]);
	bool ok = true, ok1 = true;
	for(int i = 2; i <= n; i ++) {
		if(a[i] != a[1]) ok = false;
		if(b[i] != b[1]) ok1 = false;
	}
	if(!ok && !ok1) puts("NO");
	else puts("YES");
}