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

Input: Consider Input: mQvintdwLUpClREgxv, rYnoXBtdwLUpClRwxsqX

Output: tdwLUpClR


Input: Consider Input: WjyKtxKtEYjP, vuBZJZyKtxKtXRZs

Output: yKtxKt


Input: Consider Input: tbHKNhfd, NAPwHKNhRskt


Output: HKNh