static int CountDigit5(int number)
        {
            int cnt = 0;
            while (number != 0)
            {
                int digit = number % 10;
                if (digit == 5)
                {
                    cnt++;
                }
                number /= 10;
            }
            return cnt;
        }

        static int Ending5(int number)
        {
            int cnt = 0;
            while (number != 0)
            {
                int digit = number % 10;
                if (digit == 5)
                {
                    cnt++;
                }
                else
                {
                    break;
                }
                number /= 10;
            }
            return cnt;
        }