import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
class Main {
    public static void main(String[] args) {
        System.out.println("Hello world!");
   
       int a= 0;
                  //even no formula= 2n odd = 2n+1
       int n= 9;     // n even number 
       int sum= 0;
       while (a<n)
  {
       System.out.println(2*a);
       sum = sum + 2*a;
        a++;
  } 
 
  
      System.out.println("sum of even no. is "+sum);
   
   
   
   
   
   
   
    }
}