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

Ex Input:
srPyjmTQhdFFMcQ, QQGBdtyjmTQhmfEy

Ex Output:
yjmTQh


Ex Input:
yKtQOhYvrJVH, HQsTQOhYvPP

Ex Output:
QOhYv


Ex Input:
aNaUHSjHS, UzUHSjPqpd

Ex Output:

UHSj