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

Input: Consider Input: ZyrpGdXvvtrKQIxU, CLNGdXvvtrKQDpicfqLdt

Output: GdXvvtrKQ


Input: Consider Input: RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML

Output: chtNymcsw


Input: Consider Input: CPExRZkPDmdMXoYcl, BuHAqcMZkPDmdMdo


Output: ZkPDmdM