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();
        boolean hor = true;
        boolean ver = true;
        int x = in.nextInt();
            int y = in.nextInt();
        for(int a0 = 0; a0 < n -1; a0++){
             
            int x2 = in.nextInt();
            int y2 = in.nextInt();
            if(x2!=x)
                ver = false;
            if(y2!=y)
                hor = false;
            x=x2;y=y2;
        }
        System.out.println(ver | hor ? "YES" : "NO");
    }
}