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

Ex Input:
ksRxEVrz, cOMRxEViwF

Ex Output:
RxEV


Ex Input:
yKtQOhYvrJVH, HQsTQOhYvPP

Ex Output:
QOhYv


Ex Input:
XlusAKDlIZtDv, KEeUSmusAKDlIZho

Ex Output:

usAKDlIZ