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

SOLUTION: qnJLci

PROBLEM: UiaECWZf, gRyaECWLGRl

SOLUTION: aECW

PROBLEM: BCenuyTU, OewyenuyDm

SOLUTION:
enuy