Two analogies that relate places/locations to the associated travel mode is given in the form "A : B. C : ?". "A : B" relates place A to travel mode B. Your task is to replace the question mark (?) with the appropriate travel mode for the given place C, following the "A : B" relation.

Example Input: france : airplane. museum : ?
Example Output: bus

Example Input: washington : train. museum : ?
Example Output: bus

Example Input: mars : spaceship. island : ?
Example Output:
boat