public static int literaDwa(int n)
        {
            if (n <= 0)
            {
                return 0;
            }
            else
            {
                int[] literaDwa = new int[n + 1];
                for (int i = 1; i <= n; i++)
                {

                    if (i <= 3)
                    {
                        literaDwa[i] = i-1;
                    }
                    else
                    {
                        literaDwa[i] = (literaDwa[i - 1]) + literaDwa[i - 2] -2;
                    }
                }
                return literaDwa[n];
            }

        }
        public static int rekuDwa(int n)
        {
            if (n <= 0)
            {
                return 0;
            }
            else
            {
                if (n <= 3)
                {
                    int wynik = n-1;
                    return wynik;
                }
                else
                {
                    return (rekuDwa(n - 1)) + rekuDwa(n - 2)-2;
                }
            }

        }