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

Input: Consider Input: WjyKtxKtEYjP, vuBZJZyKtxKtXRZs

Output: yKtxKt

Input: Consider Input: JzbEpAquDJFKcNvEWZxVqRV, PFiJlpAquDJFKcNcqOpMeAv

Output: pAquDJFKcN

Input: Consider Input: uUEGnoccQieiIbEjdUoYuvRF, nIrioGZIQieiIbEjVE
Output: QieiIbEj