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]: FiKGCRXutEOzMqP, xdxRXutEsl
[A]: RXutE


[Q]: FBEPoQeIVZgNmJBF, EbQzmtbTeIVZgNmJGBgKv
[A]:
eIVZgNmJ