#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,count1,a=0,b=0; 
    scanf("%d",&n);
    for(int a0 = 0; a0 < n; a0++){
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        if(x==a)
            count++;
        if(y==b)
            count1++;
        a=x;
        b=y;
    }
    if(count==n||count1==n)
        {
        printf("YES");
        }
   else
       {
       printf("NO");
       }
    return 0;
}