using System; using System.Collections; using System.Collections.Generic; class TEST{ static void Main(){ Sol mySol =new Sol(); mySol.Solve(); } } class Sol{ public void Solve(){ long U=N/2; long D=N-N/2; Console.WriteLine((D+1)*(U+1)-1); } long N; public Sol(){ N=rl(); } static String rs(){return Console.ReadLine();} static int ri(){return int.Parse(Console.ReadLine());} static long rl(){return long.Parse(Console.ReadLine());} static double rd(){return double.Parse(Console.ReadLine());} static String[] rsa(){return Console.ReadLine().Split(' ');} static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));} static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));} static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));} }