using System;

public class Hello
{
    public static int MOD = 1000000007;
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        getAns(n);
    }
    static void getAns(int n)
    {
        var dp = new int[n + 1, 4];
        for (int i = 0; i < n + 1; i++)
            for (int j = 1; j <= 3; j++) dp[i, j] = -1;
        if (n == 1) { Console.WriteLine(1); return; }
        if (n == 2) { dp[1, 1] = 1; dp[2, 2] = 1; }
        if (n >= 3) { dp[1, 1] = 1; dp[2, 2] = 1; dp[3, 3] = 1; }
        for (int i = 1; i < n; i++)
            for (int j = 1; j <= 3; j++)
            {
                if (dp[i, j] != -1)
                {
                    for (int k = 1; k <= 3; k++)
                    {
                        if (j != k && i + k <= n)
                        {
                            if (dp[i + k, k] == -1) dp[i + k, k] = dp[i, j];
                            else dp[i + k, k] += dp[i, j];
                            dp[i + k, k] %= MOD;
                        }
                    }
                }
            }
        var ans = 0L;
        for (int i = 1; i <= 3; i++)
            if (dp[n, i] != -1)
            {
                ans += dp[n, i];
                ans %= MOD;
            }
        Console.WriteLine(ans);
    }
}