using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Problem533
{
    class Program
    {
        const long M = 1000000007;

        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());

            if(N == 1 || N == 2)
            {
                Console.WriteLine(1);
                return;
            }
            else if(N == 3)
            {
                Console.WriteLine(3);
                return;
            }
            
            long[,] dp = new long[N + 1, 4];

            dp[1, 1] = 1;
            dp[2, 2] = 1;
            dp[3, 3] = 1;
            dp[3, 2] = 1;
            dp[3, 1] = 1;

            for(int i = 4; i <= N; i++)
            {
                dp[i, 1] = (dp[i - 1, 2] + dp[i - 1, 3]) % M;
                //Console.WriteLine("dp[{0},1] = {1}", i, dp[i, 1]);
                dp[i, 2] = (dp[i - 2, 1] + dp[i - 2, 3]) % M;
                //Console.WriteLine("dp[{0},2] = {1}", i, dp[i, 2]);

                dp[i, 3] = (dp[i - 3, 1] + dp[i - 3, 2]) % M;
                //Console.WriteLine("dp[{0},3] = {1}", i, dp[i, 3]);

            }

            Console.WriteLine(((dp[N,1] + dp[N, 2]) % M + dp[N,3]) % M);

        }
    }
}