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.

Example Input: drill : drill. type : ?
Example Output: keyboard

Example Input: pull : pliers. wash : ?
Example Output: soap

Example Input: crack : nutcracker. mop : ?
Example Output:
mop