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:
iron : iron. bake : ?

Ex Output:
oven


Ex Input:
eat : fork. mop : ?

Ex Output:
mop


Ex Input:
eat : spoon. spread : ?

Ex Output:

knife