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

YPeBvuJXaSLLPhKpUQ, ryjPdyuJXaSLLPhIzBeJP
uJXaSLLPh

hGyDyQYdxCCuD, BQiFOyQYdxel
yQYdx

szbQFbCyqR, kOnbQFbmB

bQFb