Project Euler 2 Even Fibonacci numbers
'''
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.
'''
from math import *
m=4000000
i1=1
i2=2
s=0
while i1<m:
print i1
if i1%2==0:
s+=i1
t=i2
i2=i1+i2
i1=t
print s