#include<bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define pb push_back
#define mp make_pair
#define Int long long
#define fs first
#define sc second
#define max(a,b) (a>b?a:b)
#define min(a,b) (a>b?b:a)
int main(){

	int n,a[11][2],i;bool cond1=true,cond2=true;
	cin>>n;
	for(i=0;i<n;i++){
		cin>>a[i][0]>>a[i][1];
	}
	for(i=1;i<n;i++){
		if(a[i][0]!=a[0][0]){
			cond1 = false;
		}
	}
	for(i=1;i<n;i++){
		if(a[i][1]!=a[0][1]){
			cond2 = false;
		}
	}
	if(cond1||cond2)cout<<"YES\n";
	else cout<<"NO\n";
	return 0;
}