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

[Q]: wkVVZREWhcSCpvCTB, ZQWhcSCpvCDVUY
[A]: WhcSCpvC


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


[Q]: Puunlzj, zqDunlGno
[A]:
unl