Two analogies that relate actions to the tools used to perform the action is given in the form "A : B. C : ?". "A : B" relates action A to tool B. Your task is to replace the question mark (?) with the appropriate tool for the given action C, following the "A : B" relation.

Ex Input:
spread : knife. cook : ?

Ex Output:
pan


Ex Input:
spread : knife. unlock : ?

Ex Output:
key


Ex Input:
cut : glass. sweep : ?

Ex Output:

broom