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

Ex Input:
lrBJDRkT, jmBJDrI

Ex Output:
BJD


Ex Input:
TTagIJmzrOTdnKr, UONmtdHJmzrOTduWo

Ex Output:
JmzrOTd


Ex Input:
RAvkixKA, wVkgvkixwPM

Ex Output:

vkix