#include<bits/stdc++.h>
#define mod 1000000007
#define max 100001
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define ll long long 

using namespace std;

int main(){
	
	int n,x[12],y[12];
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>x[i]>>y[i];
	}
	int c=0,d=0;	
	
	for(int j=1;j<n;j++){
		for(int i=0;i<j;i++){
		if(x[j]-x[i]!=0)
		{
			c=1;
			break;
			}	
		
	}
	}
	for(int j=1;j<n;j++){
		for(int i=0;i<j;i++){
		if(y[j]-y[i]!=0)
			d=1;
	}
	}
	
	if(c==1 && d==1)
		cout<<"NO\n";
	else 
	cout<<"YES\n";
	
	return 0;
}