# 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.
	
def genfib(max):
  p=1
  c=1
  while c <= max:
   yield c
   t=c
   c=p+c
   p=t

print sum(f for f in genfib(4000000) if f%2 == 0)
