#include<stdio.h>
int main()
{
 int n,xc=0,yc=0,i,j;
 scanf("%d",&n);
 int x[n],y[n];
 for(i=0;i<n;i++)
  {
   scanf("%d%d",&x[i],&y[i]);
  }

   for(j=0;j<n;j++)
    {
     if(x[0]==x[j])
      xc++;
     else if(y[0]==y[j])
      yc++;
    }

  if(xc==n||yc==n)
   printf("YES\n");
  else
   printf("NO\n");
}