#include <bits/stdc++.h>
using namespace std;
#define fo(i,a,b) for (int i = (a); i < (b); i++)

int n, x[11], y[11];
int main() {
	scanf("%d", &n);
	fo(i,0,n) scanf("%d %d", x+i, y+i);
	int g1 = 1, g2 = 1;
	fo(i,0,n-1) {
		if (x[i] != x[i+1]) g1 = 0;
		if (y[i] != y[i+1]) g2 = 0;
	}
	puts(g1 || g2 ? "YES" : "NO");

	return 0;
}