#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main() {
     int n,fx=1,fy=1,px,py;
    cin>>n;
    cin>>px>>py;
    n--;
    for(;n--;){
      int a,b;cin>>a>>b;
        if(a!=px)fx=0;
        if(b!=py)fy=0;
    }
    if(fx || fy) cout<<"YES"<<endl;
    else cout<<"NO"<<endl;
    return 0;
}