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

Q: mvIvSzMtYsfVLdaGEmef, wnzMtYsfVLdaKm

A: zMtYsfVLda
****
Q: hVQJkZyKfPoOQEukfAbXDpB, qpojyxWkZyKfPoOQEZkUI

A: kZyKfPoOQE
****
Q: WYHYixGVwi, aCQHYixlVk

A:
HYix
****