class BeekeeperServiceImpl implements BeekeeperService {

  @Override
  public long ancestorsOfQueenAt(int generation) {
    if (generation <= 0) {
      return 0;
    }
    // please refer to the link in javadoc for the reason of + 2
    return fibonacciCalculator.term(generation + 2);
  }

    BeekeeperServiceImpl(FibonacciCalculator fibonacciCalculator);

}