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

Example Input: YPeBvuJXaSLLPhKpUQ, ryjPdyuJXaSLLPhIzBeJP
Example Output: uJXaSLLPh

Example Input: nTAXUw, OWAXYU
Example Output: AX

Example Input: ueEUyQhCLVuvGCJilgp, BeOIuUhCLVuvGqnsFFu
Example Output:
hCLVuvG