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: cut : sword. spread : ?

Output: knife


Input: Consider Input: unlock : key. iron : ?

Output: iron


Input: Consider Input: cut : sword. mop : ?


Output: mop