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

Ex Input:
iYuUgULgqcAgd, kRNUgULgqFv

Ex Output:
UgULgq


Ex Input:
CiTNsbepy, DFNsbeZl

Ex Output:
Nsbe


Ex Input:
ymxbQkvLjDMfXvBzZRux, flhQyYHxQkvLjDMfXdCuN

Ex Output:

QkvLjDMfX