#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 defined = 0, fail = 0;
    int ver = 0;
    int hor = 0;
    scanf("%d",&n);
    for(int a0 = 0; a0 < n; a0++){
        int x; 
        int y; 
        scanf("%d %d",&x,&y);
        
        if (!defined) {
            if ((x == 0 && y == 0)) {
                //skip
            } else if (x == 0) {
                defined = 1;
                ver = 1;
            } else if (y == 0) {
                defined = 1;
                hor = 1;
            }
        } else {
            if (ver && x != 0) {
                fail = 1;
                break;
            } else if (hor && y != 0) {
                fail = 1;
                break;
            }
        }
        if (fail) 
            break;
    }
    
    if (fail) {
        printf("NO");
    } else {
        printf("YES");
    }
    
    return 0;
}