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

    static void Main(String[] args) {
        bool horizontal = true;
        bool vertical = true;
        int prevX = -1;
        int prevY = -1;
        
        int n = Convert.ToInt32(Console.ReadLine());
        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)
            {
                prevX = x;
                prevY = y;
            }
            else 
            {
                if( prevX != x)
                vertical = false;
                if(prevY != y)
                horizontal = false;
            }
            
            if(!horizontal && !vertical)
            {
                Console.WriteLine("NO");
                break;
            }
        }
        
        if(horizontal || vertical)
        {
            Console.WriteLine("YES");
        }
    }
}