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

SOLUTION: Qw

PROBLEM: uqazNuZhdJhw, KbnrzNuZhBdp

SOLUTION: zNuZh

PROBLEM: tCiCRQ, gIiCeB

SOLUTION:
iC