using System;

​

public class Program

{

    public static void Main()

    {

        string block = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";

        long greatestProduct = 0;

        long greatestNumbers = 0;

​

        for (int i = 0; i < (block.Length - 12); i++)

        {

            string s = block.Substring(i, 13);

            long n = long.Parse(s);

            if ((getProduct(n)) > greatestProduct)

            {

                greatestProduct = getProduct(n);

                greatestNumbers = n;

            }

        }

​

        Console.WriteLine("The greatest product " + greatestProduct + " was obtained by multiplying the digits " + greatestNumbers + ".");

​

        static long getProduct(long n)

        {

            long product = 1;

​

            while (n != 0)

            {

                product = product * (n%10);

                n = n / 10;

            }

​

            return product;

        }

    }

}