using System;

class Program
{
    static void Main()
    {
        long n = long.Parse(Console.ReadLine());

        var a = new int[n];
        var b = new int[n];
        var c = new int[n];
        a[0] = 1;
        int m = 1000000007;

        for (int i = 1; i < n; i++)
        {
            a[i] = c[i - 1] % m;
            b[i] = a[i - 1] % m;
            c[i] = (a[i - 1] + b[i - 1]) % m;
        }

        Console.WriteLine((a[n - 1] + b[n - 1] + c[n - 1]) % m);
    }
}