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

SOLUTION: MjEvR

PROBLEM: lPhVhAQZWJDrvzcEaGEwKgZAuJI, qIJDrvzcEaGDRCRrB

SOLUTION: JDrvzcEaG

PROBLEM: btjSBSPklmNo, eKUjbBSPklmqpdU

SOLUTION:
BSPklm