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

Input: Consider Input: JqdTDnZqSuSVcMsx, TEtDDnZqSuZa

Output: DnZqSu

Input: Consider Input: DGvUCrUVlUnQBShkWnfnceGasvI, NfzGUnQBShkWnpLMnY

Output: UnQBShkWn

Input: Consider Input: FvHuowDX, CWHuonUe
Output: Huo