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

Input: Consider Input: VutZiVkDQcVpQO, BDQVDyBdiVkDQcVpuvNN

Output: iVkDQcVp


Input: Consider Input: eMDNXl, ZZDNAa

Output: DN


Input: Consider Input: upuaDHjoXlguncs, TntHjoXlZZ


Output: HjoXl