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

Example Input: dxqZUOvRprXyFfjQfTWBhR, biSVjOvRprXyFfDtuFWQ
Example Output: OvRprXyFf

Example Input: mJoHBJehHtkFS, ZMrDxHBJehHtxS
Example Output: HBJehHt

Example Input: ewedRnAUqlvKJHpf, FaatrPNrxWRnAUqlvKJHCfxPARK
Example Output:
RnAUqlvKJH