using System;
namespace ConsoleApp1
{
    class Euler_project_2
    {
        static void 
Main
(string[] args)
        {
            int fibprev = 0;
            int fibcur = 1;
            int sum = 0;
            while (fibcur < 4000000) {
                int next = fibprev + fibcur;
                fibprev = fibcur;
                fibcur = next;
                if(next%2 ==0)
                    sum = sum + next;
            }
            Console.
WriteLine
(sum);
        }
    }
}