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

SOLUTION: mXnK

PROBLEM: uqDaPS, XyDaMZ

SOLUTION: Da

PROBLEM: uspFHFQpy, QzbbFHFQbo

SOLUTION:
FHFQ