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

Q: pJqqIW, Ivqqxw

A: qq
****
Q: xzMUdHcoYJFWLOILjrg, vCscoYJFWLzO

A: coYJFWL
****
Q: eGPWKqbtA, WTPWKqwxn

A:
PWKq
****