using System;

class Program {
    static void Main(string[] args) {
        //入力
        ulong N = ulong.Parse(Console.ReadLine());

        //各係数に対する配列を用意する
        ulong[] an = new ulong[N];
        ulong[] bn = new ulong[N];
        ulong[] cn = new ulong[N];
        an[0] = 1;
        an[1] = 0;
        an[2] = 0;

        bn[0] = 0;
        bn[1] = 1;
        bn[2] = 0;

        cn[0] = 0;
        cn[1] = 0;
        cn[2] = 1;

        for (ulong i = 3; i < N; i++) {
            an[i] = an[i - 3] + an[i - 2];
            bn[i] = bn[i - 3] + bn[i - 2];
            cn[i] = cn[i - 3] + cn[i - 2];
        }


        //出力
        switch (N) {
            case 1:
                Console.WriteLine("1");
                break;
            case 2:
                Console.WriteLine("2");
                break;
            case 3:
                Console.WriteLine("2");
                break;
            default:
                Console.WriteLine((an[N - 1] + 2 * bn[N - 1] + 2 * cn[N - 1]) % (Math.Pow(10, 9) + 1));
                break;
        }
    }
}