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

DwkTGsIXLfmjMV, VqRlMxtsSBkTGsIXLfmjbvI
kTGsIXLfmj

spUbdWDLWCeqr, vIuHkWDLWCQEPaz
WDLWC

hMwVBODDnWTUTkT, bFswVBODDnWIznrPSe

wVBODDnW