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

Example Input: hUpEbyvEcQ, dHpEbyvEvwsXcN
Example Output: pEbyvE

Example Input: GFhJafTV, waHhJaji
Example Output: hJa

Example Input: MkdJWRGxYgjZGHGFd, xqSlinstdJWRGxYgjEeYX
Example Output:
dJWRGxYgj