In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

Example Input: IobjElBjKvpepE, kRulBjKvvxU
Example Output: lBjKv

Example Input: nxTtNYaazlOyEBApiUSJS, BLazlOyEBCV
Example Output: azlOyEB

Example Input: ZiqmxUwqPmzmYICRJhuakB, irFFqmxUwqPmzmfjfKE
Example Output:
qmxUwqPmzm