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

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


[Q]: RwduMBkDazrwZP, UPzcwtWMBkDazrAw
[A]: MBkDazr


[Q]: fBZgjAOwSkN, PZjAOwCch
[A]:
jAOw