import java.util.*;

class Apple{ 
    private static long counter;
    private final long id = counter++; 
    public long id() { return id; } 
   
}

class AppleAndOranges{
    public static void main(String[] args){
        ArrayList<Apple> apples = new ArrayList<Apple>();

        for(int i = 0; i < 3; i++){
            apples.add(new Apple());
        }
        for(int i = 0; i < apples.size(); i++){
            System.out.println(apples.get(i).id());
        }
    }
}