#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>



struct Points{
    int x;
    int y;
};
bool Line( struct Points P[], int n,int i,int j){
 if(i<=n-2){
 
  if(j==1)
   return (P[i].x==P[i+1].x && Line(P,n,i+1,1));
  else if(j==2)
    return (P[i].y==P[i+1].y && Line(P,n,i+1,2));  
  }
    
  return true;
}
int main(){
    int n; 
    scanf("%d",&n);
    struct Points A[n];
    for(int a0 = 0; a0 < n; a0++){
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        A[a0].x = x;
        A[a0].y = y;
     }
    bool a =Line(A,n,0,1), b =Line(A,n,0,2);
    if(a||b)
        printf("YES");

    else
        printf("NO");
    
    return 0;
}