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

SOLUTION: QCQzVIo

PROBLEM: CzkPtkpMTDeNZwCPbJJn, HzpMVDeNZwCPbJVOU

SOLUTION: DeNZwCPbJ

PROBLEM: oWPzwIIoXJNkcuAnvNn, JWBIIoXJNkcuAwVBiEJ

SOLUTION:
IIoXJNkcuA