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());
        
        int kx=-1;
        int ky=-1;

        bool isVert = true;
        bool isHoriz = 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 (a0==0) {
                kx=x;
                ky=y;
            }
            else {
                if (x != kx) isVert = false;
                if (y != ky) isHoriz = false;
            }            
        }
        
        Console.WriteLine((isVert || isHoriz) ? "YES" : "NO");
        
    }
}