PROJECT EULER #2

Link to Project Euler problem 2

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

Find the sum of all the even-valued terms in the sequence which do not exceed four million.

One of those "swapping the numbers around" jobs. I do like the conditional operator (?:) too but it sometime obfuscates the code a bit.

using System;

namespace ProjectEuler
{
   class Program
   {
       static void Main(string[] args)
       {
           //Problem 2
           bool stop = false;
           int f1 = 1;
           int f2 = 2;
           int f3 = 0;
           int sum = 2;
           while (!stop)
           {
               f3 = f1 + f2;
               sum += f3 % 2 == 0 ? f3 : 0;
               stop = f3 > 4000000 ? true : false;
               f1 = f2;
               f2 = f3;
           }
           Console.WriteLine("{0}", sum);
       }
   }
}