#link: https://projecteuler.net/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.

a = 1
b = 1
maximum = 4000000
total = 0
while a < maximum:
    c = a
    a = b+c
    b = c
    if a % 2 == 0:
        total += a
print(total)
