using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class BigInteger
    {
        private int[] number;
        private int length;
        public BigInteger(long number)
        {
            string fake = number.ToString();
            this.number = new int[(int)Math.Ceiling(fake.Length/4.0)];
            length = this.number.Length;
            for (int i = fake.Length; i < this.number.Length * 4; i++)
            {
                fake = "0" + fake;
            }
            for (int i = 0; i < this.number.Length; i++)
            {
                this.number[i] = Convert.ToInt32(fake.Substring(i * 4, 4));
            }
            Array.Reverse(this.number);
        }
        private BigInteger(int[] number)
        {
            this.number = number;
            length = number.Length;
        }
        public int getLength()
        {
            return length;
        }
        public static BigInteger operator+(BigInteger first, BigInteger second)
        {
            int[] resultArr = new int[Math.Max(first.length, second.length) + 1];
            int remain = 0;
            for (int i = 0; i < resultArr.Length ; i++)
            {
                if (i < first.length && i < second.length)
                {
                    resultArr[i] = remain + first.number[i] + second.number[i];
                    remain = resultArr[i] / 10000;
                    resultArr[i] = resultArr[i] % 10000;
                }
                else if (i < first.length)
                {
                    resultArr[i] = remain + first.number[i];
                    remain = resultArr[i] / 10000;
                    resultArr[i] = resultArr[i] % 10000;
                }
                else if (i < second.length)
                {
                    resultArr[i] = remain + first.number[i];
                    remain = resultArr[i] / 10000;
                    resultArr[i] = resultArr[i] % 10000;
                }
                else
                {
                    resultArr[i] = remain;
                    remain = 0;
                }
            }
            return new BigInteger(resultArr);
        }
        public static BigInteger operator*(BigInteger first, BigInteger second)
        {
            BigInteger result = new BigInteger(new int[first.length * second.length + 1]);
            int[] biggest = (first.length >= second.length ? first.number : second.number);
            int[] smallest = (first.length < second.length ? first.number : second.number);
            int remain = 0;
            int[] temp;
            for (int i = 0; i < smallest.Length; i++)
            {
                temp = new int[biggest.Length + i + 1];
                for (int j = 0; j < biggest.Length; j++)
                {
                    temp[i+j] += remain + smallest[i] * biggest[j];
                    remain = temp[i+j] / 10000;
                    temp[i+j] %= 10000;
                }
                temp[i + biggest.Length] = remain;
                remain = 0;
                result += new BigInteger(temp);
            }
            return result;
        }
        public override string ToString()
        {
            string result = "";
            for (int i = length - 1; i >= 0; i--)
            {
                string addition = number[i].ToString();
                for (int j = addition.Length; j < 4; j++ )
                {
                    addition = "0" + addition;
                }
                result += addition;
            }
            while (result.StartsWith("0"))
            {
                result = result.Substring(1);
            }
            return result;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            BigInteger big = new BigInteger(10000);
            BigInteger notSoBig = new BigInteger(10000);
            BigInteger result = big * notSoBig;
            Console.WriteLine(big * notSoBig);
            Console.Read();
        }
    }
}