'''
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, ...

By considering the terms in the Fibonacci sequence whose values do not exceed
four million, find the sum of the even-valued terms.
'''

terms_i_want = [0]
terms = [1,2]
i=2
n=31 #last term in Fibonacci sequence that is below 4 million.
while i <= n:
    terms.append(terms[i-1]+terms[i-2])
    i = i + 1

for x in terms:
    if x%2 == 0:
        terms_i_want.append(x)

winning = sum(terms_i_want)
print(winning)