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

Q: HEVqGddewrNqiZ, iyvlddewrNXr

A: ddewrN
****
Q: pySBCdpe, AEBCdOR

A: BCd
****
Q: MFgjvwDIvCb, tLNQjvwDEGkH

A:
jvwD
****