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

Ex Input:
GHdeqnuYnQ, zzQeqnutAZ

Ex Output:
eqnu


Ex Input:
rszjOPpbXm, pnBujOPpWHz

Ex Output:
jOPp


Ex Input:
bJGSnWrvHzr, RWRFMnWrvHpBkxR

Ex Output:

nWrvH