public abstract class Exp { }

public class PlusExp extends Exp {
    public Exp e1, e2;
    public PlusExp(Exp a1, Exp a2) { e1=a1; e2=a2; }
}

public class MinusExp extends Exp {
    public Exp e1, e2;
    public MinusExp(Exp a1, Exp a2) { e1=a1; e2=a2; }
}

public class TimesExp extends Exp {
    public Exp e1, e2;
    public TimesExp(Exp a1, Exp a2) { e1=a1; e2=a2; }
}

public class DivideExp extends Exp {
    public Exp e1, e2;
    public DivideExp(Exp a1, Exp a2) { e1=a1; e2=a2; }
}

public class IntegerLiteral extends Exp {
    public String f0;
    public IntegerLiteral(String n0) { f0 = n0; }
}

public class Main {
    public static void main(String args[]) {
	Exp e1 = new TimesExp(new IntegerLiteral("2"), new IntegerLiteral("1"));
    }
}