using System;
using System.Collections.Generic;

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("2");
            //1
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4");
            //3
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("49993");
            //407466683
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        const int Hou = 1000000007;

        List<string> InputList = GetInputList();
        int N = int.Parse(InputList[0]);

        //場合の数[現在位置,前のStep数]なDP表
        int[,] DPArr = new int[N + 1, 4];
        DPArr[0, 0] = 1;

        for (int I = 0; I <= N; I++) {
            for (int J = 0; J <= 3; J++) {
                if (DPArr[I, J] == 0) continue;

                //歩数の候補
                var HosuuList = new List<int>() { 1, 2, 3 };
                HosuuList.Remove(J);

                foreach (int EachHosuu in HosuuList) {
                    int NewI = I + EachHosuu;
                    if (NewI > N) break;

                    int NewJ = EachHosuu;

                    DPArr[NewI, NewJ] += DPArr[I, J];
                    DPArr[NewI, NewJ] %= Hou;
                }
            }
        }

        int Answer = 0;
        for (int J = 1; J <= 3; J++) {
            Answer += DPArr[N, J];
            Answer %= Hou;
        }
        Console.WriteLine(Answer);
    }
}