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

Example Input: XpFCxFOgTTNCnQzMnVPV, FMqzdOwgTTNCnQzedorxVPe
Example Output: gTTNCnQz

Example Input: OFbCjZDoRRlLsMU, DcCjZDoRRtld
Example Output: CjZDoRR

Example Input: JzOIMEEwAirONX, GNfCMEEwAiXzkVpg
Example Output:
MEEwAi