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

wXGerDNhSNnCCedyzskswVnh, BfFNhSNnCCedybrUbI
NhSNnCCedy

slTUxy, oqTUYa
TU

oYoqbAkszbtttGo, WiIFQbAkszbttYXFNsIHo

bAkszbtt