Given the task definition, example input & output, solve the new input case.
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
Example: PPdQTlHHTJEe, DydQTlHHVnmlLu
Output: dQTlHH
Here, 'dQTlHH' is the longest common substring in both the input strings 'PPdQTlHHTJEe' and 'DydQTlHHVnmlLu'.

New input case for you: UfATWzCRiucfw, VGMATWzCRrjKa
Output:
ATWzCR