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: PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs

SOLUTION: zvmYrlGZgO

PROBLEM: fbDJTFXnnyhXamFwB, xphEDJTFXnnyhXrzD

SOLUTION:
DJTFXnnyhX