Project Euler 2 - Even Fibonacci Numbers

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, ...

By considering the terms in the Fibonacci sequence whose values do not exceed four million, 

find the sum of the even-valued terms.

Official link: https://projecteuler.net/problem=2