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

Example Input: DhhYhrqVMXSoyvXQwqPKzWARAP, CaMXSoyvXQwqcDDtMsVqD
Example Output: MXSoyvXQwq

Example Input: wbFDXJQDQxQJzudOUlR, QEbsIDXJQDQxQsSYIutwU
Example Output: DXJQDQxQ

Example Input: sSzFByBavZkzAlJnwa, wEoWyBavZkzWwND
Example Output:
yBavZkz