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

[Q]: YlhtTQgHiffTbIbBrcHMqFKCdWz, HyregFgMffTbIbBrcHYUnnQvGlx
[A]: ffTbIbBrcH


[Q]: gTjTwC, OUjTgM
[A]: jT


[Q]: ynHMaRnKrC, KBKFjHMaRnKDa
[A]:
HMaRnK