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

GlAYDsKQoXy, IxDsKQuK
DsKQ

DUhUbmfLuOFAQann, kwnzfLuOFAErR
fLuOFA

pKLIHcmndJcmygRNmW, nXcmndJcmygtl

cmndJcmyg