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

Input: Consider Input: CkZOSZevST, bbZOSZIg

Output: ZOSZ


Input: Consider Input: RwqzMTeLMdPx, qaWtYhqzMTeLMdHbWDT

Output: qzMTeLMd


Input: Consider Input: xmrPCtuoBg, VDvGPCtuovn


Output: PCtuo