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

SOLUTION: JAkt

PROBLEM: nrIHKzJCdAQzUDRBYpg, JDzJCdAQzUMMYrLcfO

SOLUTION: zJCdAQzU

PROBLEM: jVQKVZlgrJRuwuAYS, nUgcjFSgrJRuwuWWtD

SOLUTION:
grJRuwu