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]: GnElFKBIoYmAdvz, GrElFKBIoMo
[A]: ElFKBIo


[Q]: GhPNaPxe, XkPNawt
[A]:
PNa