#include <bits/stdc++.h>
using namespace std;
#define pf printf
#define sf scanf
#define bug printf("fuck\n");

typedef long long int  LL ;





int main () {


      LL n ;
      cin >> n ;
      LL i ;
      LL x[n] ,y[n]
 ;      for ( i = 0 ; i < n ;i++ ) {
            cin >> x[i] >> y[i] ;

      }
      bool f1 = true , f2 = true ;

      for ( i = 0; i < n-1 ;i ++)  {

            if(x[i]!=x[i+1]) f1 = false ;
            if ( y[i] != y[i+1]) f2 = false;



      }
      if ( f1 || f2) cout<<"YES" <<endl;
      else cout <<"NO"<<endl;
      return 0 ;





}