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

SOLUTION: FonizDqCVv

PROBLEM: AeYjeKwZQillzpD, SnqviKwZQillrxuTB

SOLUTION: KwZQill

PROBLEM: vGADFaF, kQADFXNf

SOLUTION:
ADF