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

Input: Consider Input: WFAPUCgVYbmZiFlacUzyv, xQFiekrgPUCgVYbmZUEtl

Output: PUCgVYbmZ


Input: Consider Input: QqtCFzXHPNFXx, XECFzXHPSGwUuk

Output: CFzXHP


Input: Consider Input: AIakYrqjsZXjUP, GMYYrqjsZOKCmW


Output: YrqjsZ