using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.IO;
using System.Collections;

namespace MultiplyBigNumbers
{
    class MainProgram
    {
        public const int length = 100;
        public const int lengthIndex = 99;

        public const int n = 199;
        public const int nIndex = 198;

        public const string readFile = "numbers.txt";
        public const string writeFile = "answers.txt";

        static void Main(string[] args)
        {
            Stopwatch st = new Stopwatch();
            st.Start();

            RunProcess();

            st.Stop();
            Console.WriteLine("Elapsed = {0}.", st.Elapsed.ToString());

            if (Stopwatch.IsHighResolution)
                Console.WriteLine("Timed with high resolution.");
            else
                Console.WriteLine("Not timed with high resolution.");

            Console.ReadLine();
        }

        #region RunProcess

        private static void RunProcess()
        {
            StreamReader sr = new StreamReader(readFile);
            StreamWriter sw = new StreamWriter(writeFile, false);

            string numberString1;
            string numberString2;

            while (!sr.EndOfStream)
            {
                numberString1 = sr.ReadLine();
                numberString2 = sr.ReadLine();

                sw.WriteLine(MultiplyStrings(numberString1, numberString2));
            }
        }

        #endregion

        public static string MultiplyStrings(string numberString1, string numberString2)
        {
            StringBuilder result = new StringBuilder();

            int[] string1Transform = new int[length];
            int[] string2Transform = new int[length];

            int j;
            int k;
            int answer;
            int carryover = 0;

            int i = lengthIndex;
            while (i > -1)
            {
                string1Transform[i] = Convert.ToInt32(numberString1[i].ToString());
                string2Transform[i] = Convert.ToInt32(numberString2[i].ToString());

                j = i;
                k = lengthIndex;
                while (j < length)
                {
                    carryover += string1Transform[j] * string2Transform[k];
                    j++;
                    k--;
                }
                answer = carryover;
                carryover = answer / 10;
                answer -= carryover * 10;

                result.Insert(0, answer.ToString(), 1);
                i--;
            }

            i = length;
            while (i < n)
            {
                j = 0;
                k = nIndex - i;
                while (k > -1)
                {
                    carryover += string1Transform[j] * string2Transform[k];
                    j++;
                    k--;
                }
                answer = carryover;
                carryover = answer / 10;
                answer -= carryover * 10;

                result.Insert(0, answer.ToString(), 1);
                i++;
            }
            result.Insert(0, carryover.ToString(), 1);

            return result.ToString().TrimStart(new char[] { '0' });
        }
    }
}