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

SOLUTION: QHJ

PROBLEM: euQWhCovKplukMYznXcD, XAfMhKdzhCovKplukMcMlSuBw

SOLUTION: hCovKplukM

PROBLEM: yRKOwRYhckpCElJ, cLoNKOwRYhckpeaSNAP

SOLUTION:
KOwRYhckp