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

SOLUTION: YuZvA

PROBLEM: XEvxzelZaWRO, zXIelZaWBUn

SOLUTION: elZaW

PROBLEM: WjyKtxKtEYjP, vuBZJZyKtxKtXRZs

SOLUTION:
yKtxKt