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

[Q]: CkZOSZevST, bbZOSZIg
[A]: ZOSZ


[Q]: QECPAHsg, bUfPAHOWb
[A]: PAH


[Q]: jIGGsXamke, uqBvGsXaHbt
[A]:
GsXa