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

Ex Input:
aeQjEeiWGONmzGimhGiw, RIEeiWGONmOZuVYr

Ex Output:
EeiWGONm


Ex Input:
iaXeqfIrYKxPJRXxfSm, rIYKxPJRXxfsjVsqe

Ex Output:
YKxPJRXxf


Ex Input:
OGZdZcwHfwWgVktru, EwcwHfwWwjK

Ex Output:

cwHfwW