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

Q: DZfOjrQffR, CXOjrQQc

A: OjrQ
****
Q: nxoXDohHr, WcbkXDohFbJ

A: XDoh
****
Q: jWwwGRaUxtqg, izOGRaUtY

A:
GRaU
****