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

Input: Consider Input: HiGmCdXrmFRJYWLvZbpU, IxhkrmFRJYWLvZLaqRVxPkL

Output: rmFRJYWLvZ


Input: Consider Input: DGvUCrUVlUnQBShkWnfnceGasvI, NfzGUnQBShkWnpLMnY

Output: UnQBShkWn


Input: Consider Input: oWsEhOf, HGfsEhefN


Output: sEh