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

Ex Input:
hGyDyQYdxCCuD, BQiFOyQYdxel

Ex Output:
yQYdx


Ex Input:
lsNwypFwhKP, diEfLwypFwEKqCN

Ex Output:
wypFw


Ex Input:
BXSemHXVifDFztPlfYmqcey, wvrgeFAWLVifDFztPlNlMIVBSF

Ex Output:

VifDFztPl