using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static void Main(String[] args) {
        int n = Convert.ToInt32(Console.ReadLine());
        var sameAxis = true;
        for(int a0 = 0; a0 < n; a0++){
            string[] tokens_x = Console.ReadLine().Split(' ');
            int x = Convert.ToInt32(tokens_x[0]);
            int y = Convert.ToInt32(tokens_x[1]);
            
            if(x > 0 && y > 0){
                sameAxis = false;
                break;
            }  
        }
        
        Console.WriteLine(sameAxis ? "YES" : "NO");
    }
}