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


class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		if( A() && B() || C() && D() ){
			System.out.println("done...");
		}
	}
	
	public static boolean A(){
		System.out.println("This is class A");
		return true;
	}
	
	public static boolean B(){
		System.out.println("This is class B");
		return true;
	}
	
	public static boolean C(){
		System.out.println("This is class C");
		return true;
	}
	
	public static boolean D(){
		System.out.println("This is class D");
		return true;
	}
	
}