\includegraphics{https://static.e-olymp.com/content/95/95f551fa1ebf2cb6e1eb104418d2215e13b5a781.gif} Mom baked a birthday Sergei large and delicious cake round and asked him to cut it himself. At his disposal is rather a long knife, which allows to cut across the cake, however, because communication with the cutting tool is always fraught with certain dangers, Serge wants to make a minimum number of cuts, so that all the guests got at least one piece. Naturally, he must not forget that and he should get all the holiday table at least one piece of mom's cake, but Sergei is absolutely not interested in any size and shape of pieces of cake will be - for him the main thing that they all had the same thickness, as my mother baked a cake. Please note that guests can come for Sergei enough. \InputFile One number - the number of guests \textbf{n} (\textbf{n} < \textbf{210000001}). \OutputFile The desired number of cuts \textbf{k}.