#include <iostream>

using namespace std;

int main(){

	int n;
	cin >> n;
	int p[n][2];
	
	cin >> p[0][0] >> p[0][1];
	int x = p[0][0];
	int y = p[0][1];
	int c = 0,c1= 0;
	for(int i = 1; i< n; i++){
		cin >> p[i][0] >> p[i][1];

		if(x != p[i][0]) c = 1;
		if(y != p[i][1]) c1 = 1;
 	}

 	if(c == 1 && c1 == 1)cout<< "NO"<<endl;
 	else cout<<"YES"<<endl;
	
	
	return 0;
}