Assignemnt #76 and Collatz Sequence

Code
/// Name: Yordan Rashkov
/// Period: 7
/// Program Name: Collatz Sequence
/// File Name: CollatzSequence.java
/// Date Finished: 2/3/2016

import java.util.Scanner;

public class CollatzSequence

{
 
 public static void main( String[] args )
    
    {
     
     Scanner keyboard = new Scanner(System.in);
    
    int num;
        
        
        System.out.println( "Starting number: " );
        num = keyboard.nextInt();
        
        while ( num <= 0 )
        {
            System.out.println( "The number that you entered must be greater than 0! Please try again! " );
            num = keyboard.nextInt();
        }
        while ( num != 1 )
        {
            if ( num % 2 == 0 )
            {
            num = num / 2;
            System.out.println( num);
                
                 }
            
           
            else if ( num % 2 != 0 )
                {
                    num = (num * 3) + 1;
            System.out.println( num);
                }
        }
    }  
}