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

Input: Consider Input: qMnjlfIsQRtUlPggCpHqu, gfVndMwYDIsQRtUlPgqBJKCX

Output: IsQRtUlPg


Input: Consider Input: xzMUdHcoYJFWLOILjrg, vCscoYJFWLzO

Output: coYJFWL


Input: Consider Input: OqKrAoAorQOqH, YVxUKrAoAorQtz


Output: KrAoAorQ