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

SOLUTION: QDdYwemF

PROBLEM: osmJJcZlDAXBgJFsJKa, rzPNlDAXBgJYrgXlH

SOLUTION: lDAXBgJ

PROBLEM: oXOPKi, jJOPOd

SOLUTION:
OP