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

Q: gfXPLNzsyfEotmHL, oJeXPLNzsyJuXP

A: XPLNzsy
****
Q: VLxrvK, gvxrac

A: xr
****
Q: apGMPThLTCw, LvMPThYW

A:
MPTh
****