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

Q: eeoJEtGHPDvHck, ezPGHPDvHSf

A: GHPDvH
****
Q: oiNEYHxbvAb, bcDDdEYHxbCREd

A: EYHxb
****
Q: WAIjytb, VinIjyieI

A:
Ijy
****