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

HEVqGddewrNqiZ, iyvlddewrNXr
ddewrN

hVQJkZyKfPoOQEukfAbXDpB, qpojyxWkZyKfPoOQEZkUI
kZyKfPoOQE

IbWSAfftknp, dAmAfftNA

Afft