Euler50

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

namespace Euler50
{
    class Program
    {
        static void Main(string[] args)
        {
          
            int sum = 0;
            int firstAddedPrime = 2;
            int lastAddedPrime = 2;
           
            
            while (sum+GetNextPrime(lastAddedPrime) < 1000000 )
            {
                sum += lastAddedPrime;
                lastAddedPrime=GetNextPrime(lastAddedPrime);

            }
         
            while (!IsPrime(sum))
            {
                sum -= firstAddedPrime;
                firstAddedPrime = GetNextPrime(firstAddedPrime);
            }
           
            Console.WriteLine(sum);
          

        }
       
        public static int GetNextPrime(int n = 1)
        {
            int i = n + 1;
            while (!IsPrime(i))
            {
                i++;
            }
            return i;
        }
        public static bool IsPrime(int n)
        {
            int result = 0;
            int start = 2;
            int end = n;
            for (int i = start; i < end; i += 1)
            {
                if (n % i == 0)
                {
                    start = i;
                    end = n / i;
                    result += start == end ? 1 : 2;
                }

            }
            return result==0;
        }

    }
}