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

Ex Input:
CkZOSZevST, bbZOSZIg

Ex Output:
ZOSZ


Ex Input:
AxRSlkQfWHrdlgQG, iXIOrmlkQfWHTy

Ex Output:
lkQfWH


Ex Input:
hhjWyIsUaAbHppgKqr, jyCGqGlIsUaAbHppcly

Ex Output:

IsUaAbHpp