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

Ex Input:
wbdHVigIkjNkuAmbr, iSgIkjNkQYyn

Ex Output:
gIkjNk


Ex Input:
KvPFobZEGs, eKFobZEtnm

Ex Output:
FobZE


Ex Input:
WtlDqzOIOIG, UzaqzOIOQBK

Ex Output:

qzOIO