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

SOLUTION: pEbyvE

PROBLEM: QqtCFzXHPNFXx, XECFzXHPSGwUuk

SOLUTION: CFzXHP

PROBLEM: mGCBSVYJmMfgVRapKr, FovRJmMfgVRJmRa

SOLUTION:
JmMfgVR