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

Q: aZcGMvzBhazkCIFqpVe, AOljBvzBhazkWXeTuA

A: vzBhazk
****
Q: feYKRk, PrYKMW

A: YK
****
Q: iuZHQxAeJdXq, kiXlQxAeJAwSxt

A:
QxAeJ
****