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

[Q]: iUtNuU, iKtNWk
[A]: tN


[Q]: PShMbsbexXGlpBuMMDZZS, sVqGxSexXGlpBxuHXoI
[A]: exXGlpB


[Q]: zJrMgfaspc, SbQFrMgfgc
[A]:
rMgf