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

[EX Q]: mCxQTIaXN, mWQTIaxzPT
[EX A]: QTIa

[EX Q]: BmwpAnWJ, klVwpAFw
[EX A]: wpA

[EX Q]: NLgxIfPaSn, VdaIfPadkZF
[EX A]:
IfPa