import java.rmi.*;
import java.rmi.server.*;

public class ComputeEngine extends UnicastRemoteObject implements Counter {
    
    public ComputeEngine() throws RemoteException {
        super();
        value = 0;
    }
    
    int value;
    
    @Override
    public int next() {
        return ++value;
    }
    
    @Override
    public int prev() {
        return --value;
    }
    
}