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

Example Input: OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq
Example Output: ERnjubLF

Example Input: yJRITYgVTSNsPjG, NSIdKYgVTSNmj
Example Output: YgVTSN

Example Input: prvoGsabpiVOyhigeUcRSAcNrlpRd, wMlPJiVOyhigeUcfiAslBKUhh
Example Output:
iVOyhigeUc