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

oiNEYHxbvAb, bcDDdEYHxbCREd
EYHxb

RJMYumLAlhmnbhzKRzIOWsGrxGu, VEViqlihmnbhzKRzIBArjAhYrz
hmnbhzKRzI

TzOUkGtHZwIyk, VmkGtHZwIzKQHC

kGtHZwI