Reciprocal cycles #26

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

//A unit fraction contains 1 in the numerator.The decimal representation of the unit fractions with denominators 2 to 10 are given:

//1/2   =   0.5
//1/3   =   0.(3)
//1/4   =   0.25
//1/5   =   0.2
//1/6   =   0.1(6)
//1/7   =   0.(142857)
//1/8   =   0.125
//1/9   =   0.(1)
//1/10  =   0.1
//Where 0.1(6) means 0.166666..., and has a 1-digit recurring cycle.It can be seen that 1/7 has a 6-digit recurring cycle.

//Find the value of d< 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part.
namespace _26
{
    class Program
    {
        static void Main(string[] args)
        {
            BigInteger a =(BigInteger.Pow(10,982)-1)/983;
            Console.WriteLine(a.ToString().Length);
        }
    }
}