using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var x = stepPerms(7);

        //foreach(int a in x)

        //{

            Console.WriteLine(x);

        //}

    }

    static int stepPerms(int n) {

        int []s = new int[3]{1,2,3};

        if( n == 0)

            return 1;

        var nums = new int[n+1];

        nums[0] = 1;

        for(int i=1; i < nums.Length; i++)

        {

            Console.WriteLine("i===> " + i);

            int total = 0;

            for(int k= 0; k < s.Length; k++)

            {

                Console.WriteLine("k===> " + k + ", s[k]==> " + s[k]);

                if(i-s[k] >=0)

                {

                    total += nums[i-s[k]];

                }

            }

            Console.WriteLine("----------------------" + total);

            nums[i] = total;

        }

        return nums[n];

    }

​

}