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

Ex Input:
sJRFPufsaWXNeu, AePufsafc

Ex Output:
Pufsa


Ex Input:
GoodBOwvrki, kRCsdBOwvrakgiH

Ex Output:
dBOwvr


Ex Input:
GHdeqnuYnQ, zzQeqnutAZ

Ex Output:

eqnu