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

Ex Input:
gwVLygvd, VOQLyglfo

Ex Output:
Lyg


Ex Input:
bjjsMtBzzXIgYWPBZmaDL, iTxktmvBzzXIgYWPhbAyBE

Ex Output:
BzzXIgYWP


Ex Input:
YhjsrHapY, qXtsrHaeFid

Ex Output:

srHa