ThousandDigit(Long)

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

namespace ThousandDigit
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.SetIn(new StreamReader(@"E:\testInput\Input.txt"));
            Console.SetOut(new StreamWriter(@"E:\testInput\Output.txt") { AutoFlush = true});

            const int WINDOW = 13;

            string str = Console.ReadLine();

            char[] ch = str.ToCharArray();

            int sp = 0;
            int fp = sp + WINDOW;
            long maxProduct = 0;

            
            while(fp != ch.Length - 1) {
                var currentList = ch
                             .Where((c, i) => i >= sp && i < fp)
                             .Select(x => (long)Char.GetNumericValue(x)).ToList();


                var currentProduct = currentList
                             .Aggregate((p, cc) => cc * p);


                if(maxProduct <= currentProduct)
                    maxProduct = currentProduct;

                sp++;
                fp = sp + WINDOW;
            }


            Console.WriteLine(maxProduct);
          

            //foreach (var x in List)
            //    Console.WriteLine(x);




        }
    }
}