This is a Project Euler problem. If you don't want to see candidate solutions don't look here.

Hello you all! im developping an application that will find the sum of all even terms of the fibonacci sequence. The last term of this sequence is 4,000,000 . There is something wrong in my code but I cannot find the problem since it makes sense to me. Can you please help me?

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            long[] arr = new long [1000000] ;
            long i= 2;
            arr[i-2]=1;
            arr[i-1]=2;
            long n= arr[i];

           long s=0;
            for (i=2 ; n <= 4000000; i++)
            {

                arr[i] = arr[(i - 1)] + arr[(i - 2)];
            }
            for (long f = 0; f <= arr.Length - 1; f++)
            {
                if (arr[f] % 2 == 0)
                    s += arr[f];
            }
            Console.Write(s);
            Console.Read();

        }
    }
}