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: JXnHYuZvAYK, zhUYuZvASGhd

SOLUTION: YuZvA

PROBLEM: cQvdNwNQYBgzXZIAHYSy, MxtBgzNwNQYBgzXZpqsRyRyJep

SOLUTION:
NwNQYBgzXZ