#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define pb push_back
#define F first
#define S second
#define maxn 100005
#define mod 1000000007
pair<int,int>p[15];
int main(){
  ios::sync_with_stdio(false);
  
  int n;
  cin>>n;
  int f1=0,f2=0;

  for(int i=0;i<n;i++)cin>>p[i].F>>p[i].S;

  for(int i=1;i<n;i++){
    if(p[i].F!=p[i-1].F)f1=1;
  }

  for(int i=1;i<n;i++){
    if(p[i].S!=p[i-1].S)f2=1;
  }

  if(f1==1&&f2==1){
    cout<<"NO\n";
  }
  else cout<<"YES";

  return 0;
}