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 [] x = new int[n];
        int [] y = new int[n];
        boolean xb = true ;
        boolean yb = true ;
        
        for(int a0 = 0; a0 < n; a0++){
             x[a0] = in.nextInt();
             y[a0] = in.nextInt();
        }       
        
        for(int a0 = 0; a0 < n-1; a0++){
            if(x[a0] != x[a0+1] )
                xb = false ;
            if(y[a0] != y[a0+1] )
                yb = false ;            
        }
       
        
        if(xb || yb)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}