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

SOLUTION: yZ

PROBLEM: TdvkBvVyJcSdYGGPfnyml, rIvIvVyJcSdYhtxG

SOLUTION: vVyJcSdY

PROBLEM: qksphCiWsSwHK, LBsphCiWsSrplpg

SOLUTION:
sphCiWsS