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

OXdSmcKG, XbDdSmJl
dSm

RwduMBkDazrwZP, UPzcwtWMBkDazrAw
MBkDazr

gXELViYHqCTOJefpR, IUYHqCTOFl

YHqCTO