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

SOLUTION: AX

PROBLEM: XqyPjqNZDEK, EfwPjqNgjIP

SOLUTION: PjqN

PROBLEM: AwBKKNmOALlzh, FBJhzKKNmOrdDvB

SOLUTION:
KKNmO