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

int main(){
    int n,count_x=1,count_y=1; 
    scanf("%d",&n);
    int x1,y1;
    scanf("%d %d",&x1,&y1);
  
   
    
    for(int a0 = 0; a0 < n-1; a0++)
    {
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        if(x1==x)
            count_x++;
        else if(y1==y)
            count_y++;
        
            
         
    }
    if (count_x==n || count_y==n)
        printf("YES\n");
    else
        printf("NO\n");
    return 0;
}