In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

zeuyZKwvIOfx, BlmZKwvspUt
ZKwv

jexvmCmveGzFUimQMx, RVwOSJveGzFUimrcOwjEwe
veGzFUim

dwZvbFjTBlzC, uNbFjTBNYriV

bFjTB