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

RpaZAvSnEBgGapIPQgw, wcwYsXvSnEBgGapIwoIWROB
vSnEBgGapI

zeuyZKwvIOfx, BlmZKwvspUt
ZKwv

IeqjHBqwOHMkXZu, UBEfkHBqwOHjUrDu

HBqwOH