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

XqyPjqNZDEK, EfwPjqNgjIP
PjqN

QlJnxO, BLJnCQ
Jn

PrwXeYEvnkkDHAZXjZDFLQKY, NLhnkkDHAZXagW

nkkDHAZX