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

Input: Consider Input: HKqfdEvqDuGhWByFlzIEeYh, VVaZfkLCMuGhWByFlzIOZaXbMCA

Output: uGhWByFlzI

Input: Consider Input: bdCOjNchdKtvWzOI, FwejNchdKhEd

Output: jNchdK

Input: Consider Input: aXzFHbmOouA, MrhuRFHbmORtw
Output: FHbmO