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

Q: NxgzLSzFGa, JvLzLSzsuj

A: zLSz
****
Q: rszjOPpbXm, pnBujOPpWHz

A: jOPp
****
Q: YSNxBiptdfeVXjFlwM, hRSptdfeVXGm

A:
ptdfeVX
****