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

oXZmCSdFrMumlZcP, eFpOZmCSdFrIuHeS
ZmCSdFr

FCKbAgSVgj, wAEAWbAgSVSVwD
bAgSV

jjcdiruvcdbbDbir, UgkuvcdbbDbFumGsmRT

uvcdbbDb