# coding=utf-8

''' 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. '''

fib = [1, 1, 0] # 设置 fib 数列循环的数组
i = 1 # fib 数列的项计数器
total = 0 # 满足条件的数的和
while fib[i] <= 4000000: # fib 数列小于要求值时不断循环
  if fib[i] % 2 == 0:
    print fib[i]
    total += fib[i] # 满足条件的项计入总和
  i = (i + 1) % 3 # 项计数器
  fib[i] = fib[(i + 1) % 3] + fib[(i + 2) % 3] # 
print total # 

a, b = 2, 8
total = 0
while a < 4000000:
  total += a
  a, b = b, a + b * 4
print total