using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main() {
        long mod = (long)Math.Pow(10, 9) + 7;

        long N = int.Parse(Console.ReadLine());

        var bp = new long[2, 3];
        bp[0, 0] = 1;
        bp[0, 1] = 0;
        bp[0, 2] = 0;

        for (int i = 1; i < N; i++) {
            bp[1, 0] = bp[0, 2];
            bp[1, 1] = bp[0, 0];
            bp[1, 2] = (bp[0, 0] + bp[0, 1]) % mod;

            bp[0, 0] = bp[1, 0];
            bp[0, 1] = bp[1, 1];
            bp[0, 2] = bp[1, 2];
        }

        Console.WriteLine((bp[0, 0] + bp[0, 1] + bp[0, 2]) % mod);
    }
}