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

namespace yukicoder
{
    public class Program
    {
        public static void Main()
        {
            var n = int.Parse(Console.ReadLine());
            long q = 1000000007;
            var kk = new long[n];
            var pk = new long[n];
            var p = new long[n];
            pk[0] = 1;
            kk[1] = 1;
            p[1] = 1;
            for(var i = 2; i < n; i++)
            {
                p[i] = (pk[i - 1] + kk[i - 1]) % q;
                pk[i] = p[i - 1] % q;
                kk[i] = pk[i - 1] % q;
            }
            Console.WriteLine((kk[n - 1] + pk[n - 1] + p[n - 1]) % q);
        }
    }
}