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

Q: yiKkIxbKvNk, znaIxbKggg

A: IxbK
****
Q: vFuggVITQuctFG, hdCIWWuuggVITQwr

A: uggVITQ
****
Q: sfKNXLfVL, lFNXLTY

A:
NXL
****