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

[Q]: zeuyZKwvIOfx, BlmZKwvspUt
[A]: ZKwv


[Q]: BmxgSFWBlVX, kGgKrgSFWBlGunFcZ
[A]: gSFWBl


[Q]: uyQwjU, tnQwHY
[A]:
Qw