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

SOLUTION: kWLUJ

PROBLEM: KfjqnJLciTXqkJK, yqfRcfqnJLcisSB

SOLUTION: qnJLci

PROBLEM: TRfbsCuMGXrzUAc, jmPNVYsCuMGXrzUUMtf

SOLUTION:
sCuMGXrzU