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

Q: BUvWkxrAvDQG, rHrkxrAkCE

A: kxrA
****
Q: qMnjlfIsQRtUlPggCpHqu, gfVndMwYDIsQRtUlPgqBJKCX

A: IsQRtUlPg
****
Q: HjSczpiDvIYLZaukoHvUivtY, UiQspiDvIYLZaudVF

A:
piDvIYLZau
****