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: work : car. school : ?
Example Output: bus

Example Input: washington : train. downtown : ?
Example Output: subway

Example Input: hawaii : airplane. airport : ?
Example Output:
train