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

[Q]: CMrTXnTnTVaR, srnXnTnTDNULO
[A]: XnTnT


[Q]: UovaYpHjYSQzrfsxRfvIZE, pUOFxIKOGQzrfsxRfvIjrza
[A]: QzrfsxRfvI


[Q]: AnQteARQQMBMVAn, QcRQQMBMVcxKC
[A]:
RQQMBMV