#include<stdio.h>
#include<string.h>

struct point{
    int x;
    int y;
};
int main()
{
   int n,i,fx=0,fy=0,fst,snd;
   scanf("%d",&n);
    struct point a[n];
   for(i=0;i<n;i++)
   {
       scanf("%d%d",&a[i].x,&a[i].y);
       fst= a[0].x;
       snd=a[0].y;

       if(fst!= a[i].x)
       {
           fx=1;
       }
        if(snd!= a[i].y)
       {
           fy=1;
       }



   }

   if(fx==1 && fy==1)
   {
       printf("NO");
   }
   else{

    printf("YES");

   }






    return 0;
}