Two analogies that relate items to the associated containers is given in the form "A : B. C : ?". "A : B" relates item A to its associated container B. Your task is to replace the question mark (?) with the appropriate container for the given item C, following the "A : B" relation.

Example Input: poster : tube. cereal : ?
Example Output: box

Example Input: detergent : bottle. potatoes : ?
Example Output: sack

Example Input: vitamins : bottle. ketchup : ?
Example Output:
bottle