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

SOLUTION: WTTPho

PROBLEM: CUlMsvov, iflMsSRp

SOLUTION: lMs

PROBLEM: IKCKzvlKkQgLOJXClwNY, ToxlKkQgLOLxczocU

SOLUTION:
lKkQgLO