This question would have nothing to say, is a basic conclusion, however, I am currently very unhappy, a HNOI title, thanks to the special judge? Metamorphosis is not abnormal
Now uncomfortable one, a decomposition of the quality factor of the board question (?) Let me play for an hour, very unhappy, special judge sentenced out of 50 points? A n = 1, du [1] = 0 Let me bounced from AC WA83, do not let this little problem A happy
About the title, nothing to say, Pufer conclusion, it can not be sentenced to a pile of tree balabala, make a decomposition of the quality factor of the template, and then you'll be happy the AC