#include<iostream>
#include<bits/stdc++.h>

using namespace std;

int main(){
	int n;
	cin>>n;
	int x[n],y[n];
	for(int i=0; i<n; i++){
		cin>>x[i]>>y[i];
	}
	int fx = 0, fy = 0;
	for(int i=1; i<n; i++){
		if(x[i] != x[i-1])
			fx = 1;
		if(y[i] != y[i-1])
			fy = 1;
	}
	if(fx == 1 && fy == 1)
		cout<<"NO"<<endl;
	else
		cout<<"YES"<<endl;
	return 0;
	
}