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

Input: Consider Input: XHqQIPw, brqQIkAt

Output: qQI


Input: Consider Input: wYhGWdRC, cFGWdHEy

Output: GWd


Input: Consider Input: SUSKLl, zISKvM


Output: SK