public class Multiplica {

    static public void main(String args[])
    {
      int x=4, y=5;
      System.out.printf("%d\n", multiplica(4,5));
    }

    static public int multiplica(int x, int y)
    {
       if(y == 1) return x;
       else return (x + multiplica(x,y-1));
    }
}