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 prev_x = -1;
        int prev_y = -1;
        bool same_x = true;
        bool same_y = 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(prev_x != -1)
            {
                if(x!= prev_x) same_x = false;
                if(y!= prev_y) same_y = false;
            }
            prev_x = x; 
            prev_y = y;
        }
        Console.WriteLine(same_x || same_y?"YES":"NO");
    }
}