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

Input: Consider Input: HLtkkRnWkgIdqbQH, dWeFUtkkRnWkgIdZhlQh

Output: tkkRnWkgId


Input: Consider Input: UIjAMFDuxDDGkfQa, VdsHuxDDGkfZHZZ

Output: uxDDGkf


Input: Consider Input: ZdLuqd, wHLumO


Output: Lu