#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 val_x;
    int val_y;
    
    scanf("%d",&n);
    scanf("%d %d",&val_x,&val_y);
    for(int a0 = 1; a0 < n; a0++){
        int x;
        int y;
        scanf("%d %d",&x,&y);
        if (val_x != x)
            val_x = 42;
        if (val_y != y)
            val_y = 42;
    }
    if (val_x != 42 || val_y != 42)
        printf("YES\n");
    else
        printf("NO\n");
    return 0;
}