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 prevX = in.nextInt();
        int prevY = in.nextInt();
        boolean horiz = true;
        boolean vert = true;
        
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            
            if (x != prevX)
                horiz = false;
            if(y != prevY)
                vert = false;
            
            if ((horiz == false) && (vert == false))
                break;
        }
        
        if(horiz || vert)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}