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

SeXNqRAbKdLuWXgb, npsIWRAbKdLuUWSbvuS
RAbKdLu

uHGHiARtdJbuG, OdZmiARtdrhC
iARtd

ThtAGFz, QrtAGRQh

tAG