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

Q: LudFxiaqbX, UWMPnFxiaqikiDx

A: Fxiaq
****
Q: spUbdWDLWCeqr, vIuHkWDLWCQEPaz

A: WDLWC
****
Q: WPVhwndOpQPUEkil, YFGhwndOpQDxA

A:
hwndOpQ
****