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

SOLUTION: vlV

PROBLEM: LJJvLTK, jpFJvLqh

SOLUTION: JvL

PROBLEM: LnvJbeHvEXWrs, mugBobeHvEXWxUjXAiW

SOLUTION:
beHvEXW