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

JqdTDnZqSuSVcMsx, TEtDDnZqSuZa
DnZqSu

sRpnJlgECTHh, JXfmNJlgECKyry
JlgEC

lbuBDK, pIuBqP

uB