#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; 
    scanf("%d",&n);
    int nPrevX = 0, nPrevY = 0;
    int nXDiff = 0, nYDiff = 0;
    for(int a0 = 0; a0 < n; a0++){
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        
        if(a0 != 0)
            {
               if(nPrevX != x)
                   nXDiff = 1;
               if (nPrevY != y)
                   nYDiff = 1;
        }
        else
            {
            nPrevX = x;
            nPrevY = y;
        }
    }
    if(nXDiff == 0 || nYDiff == 0)
        printf("YES");
    else 
        printf("NO");
    return 0;
}