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

Input: Consider Input: OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq

Output: ERnjubLF

Input: Consider Input: ChKUlYUTQQBjZMZkgEed, lmQQBjZMZkgdEf

Output: QQBjZMZkg

Input: Consider Input: wWkhzctLXALOVoCulxt, UzFKuWhkhzctLXALOtPJyoIWrCB
Output: khzctLXALO