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

Example Input: IobjElBjKvpepE, kRulBjKvvxU
Example Output: lBjKv

Example Input: ztkWLUJQXxP, fYluOkWLUJKDX
Example Output: kWLUJ

Example Input: MgOdaEeaWS, zlcHiOdaEeafche
Example Output:
OdaEea