#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 xp;
    int yp;
    int xc=0;
    int yc = 0;
    scanf("%d",&n);
    scanf("%d %d",&xp,&yp);
    for(int a0 = 0; a0 < n; a0++){
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        if (xp != x) xc=1;
        if (yp != y) yc=1;
        xp = x;
        yp = y;
    }
    
    if ((xc == 1) && (yc == 1)) printf("NO\n");
    if ((xc == 1) && (yc == 0)) printf("YES\n");
    if ((xc == 0) && (yc == 1)) printf("YES\n");
    if ((xc == 0) && (yc == 0)) printf("YES\n");
    return 0;
}