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

OyXwTWbLByC, yODnTWbLWYzc
TWbL

cvRdSsuNwGVEwSSrowDpaOu, gFMcLKIeLwNwGVEwSSroUGskaoloqC
NwGVEwSSro

TdvkBvVyJcSdYGGPfnyml, rIvIvVyJcSdYhtxG

vVyJcSdY