In this task, You are given an open-domain question that can be answered based on factual information. Your task is to provide \*short\* answer (in a few words only) for the given question. The short answer can be one or more entities or it can also be boolean \*yes\* or \*no\*.

Input: Consider Input: who was ancient china's main enemy that lived to the north

Output: Sui Dynasty


Input: Consider Input: when did they change pennies from copper to zinc

Output: 1943


Input: Consider Input: when does the last episode of empire air


Output: April 18, 2018