import java.lang.reflection.*;

abstract class DoubleSingletone {

    public static void main (String args[]) {
        String S = args[0];
        getInstance(S);
    }

    private static DoubleSingletone instance = null;

    public static DoubleSingletone getInstance(String S1) {
        if (instance == null){
            String S = S1;
            Class cl=Class.forName(S)   ;   //ciąg instrukcji wywoła get instance dla klasy S
            Method m=cl.getMethod("getInstance",new Class[] {});
            instance = m.invoke(null,new Object[] {});
        }
        return instance;
    }

}

class SingletoneA extends DoubleSingletone{

    private static SingletoneA instance1 = null;
    private SingletoneA() {
    };

    private static SingletoneA getInstance() {
        instance1 = new SingletoneA();
        return instance1;
    }
    }

class SingletoneB extends DoubleSingletone{

    private static SingletoneB instance1 = null;
    private SingletoneB() {
    } ;

    private static SingletoneB getInstance() {
        instance1 = new SingletoneB();
        return instance1;
    }
    }