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

Ex Input:
fREVIdeTcakgFnwDWTVev, IbtXImseeTcakgFnwDYsKBAlux

Ex Output:
eTcakgFnwD


Ex Input:
gfDDsblwUryUw, UWaRisblwUTqTM

Ex Output:
sblwU


Ex Input:
ZOIYfkMmLnXV, irfkMmLEjbd

Ex Output:

fkMmL