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

Example Input: TdvkBvVyJcSdYGGPfnyml, rIvIvVyJcSdYhtxG
Example Output: vVyJcSdY

Example Input: eedZoMwKgDhdsgs, kMMwKgDLm
Example Output: MwKgD

Example Input: eMjBRJDpxGBIpwaxqfPHNETfLLs, lltaQxGBIpwaxqfSXD
Example Output:
xGBIpwaxqf