{-	|
	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.
-}

-- Get fib sequence
fib = 0 : 1 : zipWith (+) fib (tail fib)
-- Get up to 4000000
ans = sum [x | x <- takeWhile (<= 4000000) fib, mod x 2 == 0]

main = putStrLn (show ans)