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

Ex Input:
TUAHhdvHIBxogI, LjfGsAHhdvHJcSdNV

Ex Output:
AHhdvH


Ex Input:
IVnbnqBqdPcXfHotUzCYoaGQy, PAlyypBRRBqdPcXfHotpZs

Ex Output:
BqdPcXfHot


Ex Input:
tzakQouze, WgokQoJdo

Ex Output:

kQo