#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef long double LF;
#define ft first
#define sd second
#define pb push_back
#define MOD 1000000007
//-------------------------------------

int main(){
	int x[15], y[15];
	int n, flag1=1, flag2=1;
	cin>>n;
	cin>>x[0]>>y[0];
	for(int i=1;i<n;i++){
		cin>>x[i]>>y[i];
		if(x[i]!=x[i-1]) flag1=0;
		if(y[i]!=y[i-1]) flag2=0;
	}
	if(flag1==1 || flag2==1) cout<<"YES\n";
	else cout<<"NO\n";
	return 0;
}