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

XYnCjAWPHHJ, gmCjAWPHpmwVsm
CjAWPH

vytthSjj, XVttthSFAvk
tthS

ewAmvTOEJyFcsxUdlA, ldTQxTOEJyFcsxUHaYrGL

TOEJyFcsxU