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

YXsgPE, ENsgSO
sg

BVipiZoGXaWdjmDsxWP, yxppsiYkiZoGXaWdjoDRuKW
iZoGXaWdj

ZQXmTrSn, RSXmTraq

XmTr