fact

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

namespace FactorialWithArray
{
    class FactWithArr
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            int[] result = factorialOf(n);

            foreach (int c in result)
            {
                Console.Write(c);
            }
            Console.WriteLine();
        }
        private static int[] factorialOf(int number)
        {
            int[] result = new int[number * 2]; //Too big. Will remove NULL values later
            int total = 0;
            int rem = 0;
            int count = 0;
            int index = result.Length - 1;
            result[index] = 1;
            for (count = 2; count <= number; count++)
            {
                while (index > 0)
                {
                    total = result[index] * count + rem;
                    rem = 0;
                    if (total > 9)
                    {
                        result[index] = total % 10;
                        rem = total / 10;
                    }
                    else
                    {
                        result[index] = total;
                    }
                    index--;
                }

                total = 0;
                rem = 0;
                index = result.Length - 1;
            }

            return removeNullElementsFrom(result); //Removing NULL values. Gotta look presentable
        }

        private static int[] removeNullElementsFrom(int[] array)
        {
            int count = 0;
            for (int i = 0; i < array.Length; i++)
            {
                if (array[i] == 0)
                {
                    count++;
                    continue;
                }

                break;
            }

            if (count > 0)
            {
                int size = array.Length - count;
                int[] tmpArr = new int[size];
                Array.Copy(array, count, tmpArr, 0, size);
                array = tmpArr;
            }

            return array;
        }
    }
}