import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] points = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            points[a0] = x;
        }
        boolean sameLine = true;
        for(int i = 0; i < n; i++){
            if(i + 1 != n){
                if(points[i] != points[i+1]) sameLine = false;
            }
        }
        if(sameLine){
            System.out.println("YES");
        } else{
            System.out.println("NO");
        }
    }
}