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:
oGaGjsaKsUpLQAg, iDGjsaKsUoYGuta

Ex Output:
GjsaKsU


Ex Input:
tPrPnA, GUrPWu

Ex Output:

rP