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

SOLUTION: qq

PROBLEM: ktABEFESAVHZkkY, uMjxiESAVHZkZgWUte

SOLUTION: ESAVHZk

PROBLEM: HPafkYjAhLYtFwEBnAYwhYZ, WFaeBBehLYtFwEBSmkZxB

SOLUTION:
hLYtFwEB