#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; 
    int set = 0;
    int nox, noy;
    int lx;
    int ly;
    nox = noy = 0;
    scanf("%d",&n);
    for(int a0 = 0; a0 < n; a0++){
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        if(set == 0)
        {
            lx = x;
            ly = y;
            set = 1;
        }
        else
        {
            if(lx != x)
                nox = 1;
            if(ly != y)
                noy = 1;
        }
    }
    if(nox && noy)
        printf("NO\n");
    else
        printf("YES\n");
    return 0;
}