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());
        bool isStraight = true;
        //all would share an x co-ordinatie if they are vertical
        bool isVertical = true;
        bool isHorizontal = true;
        
        int currentX = -20;
        int currentY = -20;

        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(currentX < -10)
                currentX = x;
            
            if(currentY < -10)
                currentY = y;
            //check vertical
            isVertical &= currentX == x;
            
            //check Horizontal
            isHorizontal &= currentY == y;
        }
        Console.WriteLine(isVertical || isHorizontal ? "YES": "NO");
    }
}