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

Ex Input:
iJbjApY, ggwbjAws

Ex Output:
bjA


Ex Input:
eJPZzg, lFPZbI

Ex Output:
PZ


Ex Input:
ZWHoXCelsTqq, VswOXCelJZ

Ex Output:

XCel