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

SOLUTION: oqCMP

PROBLEM: cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx

SOLUTION: QXEFSgRZ

PROBLEM: buYtSNQdGivHkRj, YXLcRmtSNQdGtqxM

SOLUTION:
tSNQdG