using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Solution {
    static void Main(String[] args) {
        /* var n = */ Convert.ToInt32(Console.ReadLine());
        var point1 = Console.ReadLine().Split();
        int x1 = Convert.ToInt32(point1[0]), y1 = Convert.ToInt32(point1[1]);

        string line;
        var noX = false;
        var noY = false;
        while ((line = Console.ReadLine()) != null) {
            var pointI = line.Split();
            
            if (x1 != Convert.ToInt32(pointI[0])) {
                noX = true;
            }
            
            if (y1 != Convert.ToInt32(pointI[1])) {
                noY = true;
            }
            
            if (noX && noY) {
                break;
            }
        }
                
        Console.WriteLine(noX && noY ? "NO" : "YES");
    }
}