using System;

public class Hello
{
    public static int MOD = 1000000007;
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        goDp(n);
    }
    static void goDp(int n)
    {
        var dp = new long[n + 1, 3];
        dp[1, 0] = 1;
        for (int i = 2; i <= n; i++)
        {
            dp[i, 0] = dp[i - 1, 2];
            dp[i, 0] %= MOD;
            dp[i, 1] = dp[i - 1, 0];
            dp[i, 1] %= MOD;
            dp[i, 2] = dp[i - 1, 0] + dp[i - 1, 1];
            dp[i, 2] %= MOD;
        }
        var ans = 0L;
        for (int i = 0; i < 3; i++)
        {
            ans += dp[n, i];
            ans %= MOD;
        }
        Console.WriteLine(ans);
    }
}