24. The diagram below shows the options available to a traveler who is at the airport and wants to go to a particular hotel. The traveler can take a taxi directly from the airport to the hotel, but taking a train, a bus, or a boat will get her only as far as a station from which she must then take a train, a bus, or a boat to the hotel. For example, 1 option available to her (in addition to taking a taxi) is to take a train from the airport to the station and a boat from the station to the hotel. Another is to take 2 trains. Altogether, how many options for going from the airport to the hotel are available to the traveler?

(Note: All travel must be in the direction of the arrow shown on the diagram.)