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

SOLUTION: WDLWC

PROBLEM: SFQHJlK, dHfQHJoUC

SOLUTION: QHJ

PROBLEM: nREMfHuYsSMvAq, AtgMfHuYsFNu

SOLUTION:
MfHuYs