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

Input: Consider Input: yKtQOhYvrJVH, HQsTQOhYvPP

Output: QOhYv


Input: Consider Input: XSnVeAjWLFWTgwmf, WsByLAjWLFWnQfl

Output: AjWLFW


Input: Consider Input: LKKKGYtzKZHNrESF, HiRNuUwtzKZHNrcRPnq


Output: tzKZHNr