using System;

namespace y
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            long k = 1;
            long kk = 0;
            long p = 0;

            for (int i = 2; i <= n; i++)
            {
                var k2 = p % 1000000007;
                var kk2 = k % 1000000007;
                var p2 = (k + kk) % 1000000007;
                k = k2;
                kk = kk2;
                p = p2;
            }
            Console.WriteLine(n == 1 ? 1 : (k + kk + p) % 1000000007);
        }
    }
}