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.

Input: Consider Input: clamp : clamp. wash : ?

Output: soap


Input: Consider Input: vacuum : vacuum. spread : ?

Output: knife


Input: Consider Input: scrub : brush. unlock : ?


Output: key