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

ktABEFESAVHZkkY, uMjxiESAVHZkZgWUte
ESAVHZk

lkFGXvTkKm, wwELXvTkcOnG
XvTk

WKbrPlTptuaNvsjNpB, NwMflJPlTptuanAbG

PlTptua