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 horizontal = true;
        boolean vertical = true;
        int lastx = 0;
        int lasty = 0;
        
        for(int i = 0; i < n; i++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(0!=i){
                if(x!=lastx){horizontal=false;}
                if(y!=lasty){vertical=false;}
            }
            lastx = x;
            lasty = y;
        }
        
        if(horizontal || vertical){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
}