TASK DEFINITION: In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
PROBLEM: HKCoXQsLRtowYJ, PGRzNUQsLRtoLcqkn

SOLUTION: QsLRto

PROBLEM: PGjDRPDzGaBR, rpIJRPDzWi

SOLUTION: RPDz

PROBLEM: RMurrwPjlfG, QBKrrwPDkTM

SOLUTION:
rrwP