Legobreath

# euler2.py

# Each new term in the Fibonacci sequence is generated by adding the 
# previous two terms.
# By starting with 1 and 2, the first 10 items 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.

even sum = 0
a, b = 0, 1

while b < 4000000:
    a, b = b, a+b
    if (b % 2 == 0):
        evensum = evensum + b

print evensum