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: OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq
Example Output: ERnjubLF

Example Input: hQzjekPMjmvkYnMAvzn, AnjekPMjmvkYiu
Example Output:
jekPMjmvkY