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

Ex Input:
wLLwjL, arLwXm

Ex Output:
Lw


Ex Input:
zRwQdelc, UdAUwQdejhe

Ex Output:
wQde


Ex Input:
MqvZGrnqvELgJA, kIKJrvZGrnqvELBUvYU

Ex Output:

vZGrnqvEL