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

OyrqfQQnzOFUzrkDM, iBkQQnzOFewhjvO
QQnzOF

ICizmXnKMpUH, oDrnmXnKgWXX
mXnK

rRvrQMAtLufBWnh, nzrMAtLufBxSdoy

MAtLufB