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

Q: yQCDWefwvrPP, RwoMDWefwhSxTR

A: DWefw
****
Q: UZbmGVDzIaf, qfHwqGVDzIsd

A: GVDzI
****
Q: uDIzXBwmahKYyoMc, OLSBHIzXBwmaXMbgb

A:
IzXBwma
****