string Result = null;
            int carry = 0;
            int Sum = 0;
            for (int i = max - 1; i >= 0; i--)
            {
                carry = (carry + first[i] + second[i]) / 4;
                Sum = ((carry + first[i] + second[i]) % 4) + Sum;
                Result = Sum.ToString() + Result;
            }
            return (Result);