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

Example Input: edjRAatlaiCmWkpqMh, qDZYVWCDTRAatlaiCmYH
Example Output: RAatlaiCm

Example Input: cCDTMXjGMNikONun, jpcMXjGMNizBEWQzT
Example Output: MXjGMNi

Example Input: RnBdNYjQLoYdTNKGoVrFWeIzi, QiLoYdTNKGozdtQcwSM
Example Output:
LoYdTNKGo