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

SOLUTION: xr

PROBLEM: eedZoMwKgDhdsgs, kMMwKgDLm

SOLUTION: MwKgD

PROBLEM: BNkXuiRvkNbMJ, EKrqazdpXuiRvkNbKB

SOLUTION:
XuiRvkNb