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

Ex Input:
SUgXyznbUQRpiLUTlRb, jlnwLTnbUQRpioUFyJ

Ex Output:
nbUQRpi


Ex Input:
FSwxBJ, iTwxAa

Ex Output:
wx


Ex Input:
JcWlInj, kTNWlITi

Ex Output:

WlI