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());
        Stack<int> originPoint = new Stack<int>();
        Stack<int> originPointY = new Stack<int>();
        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]);
            originPoint.Push(x);
            originPointY.Push(y);
        }
        int counter = 0;
        foreach(int i in originPoint) {
            if(i == originPoint.Peek()) {
                counter++;
            }
        }
        int counter1 = 0;
        foreach(int i in originPointY) {
            if(i == originPointY.Peek()) {
                counter1++;
            }
        }
        if(counter == n || counter1 == n) {
            Console.WriteLine("YES");
        }else{
            Console.WriteLine("NO");
        }
    }
}