#!/usr/bin/perl
#
# 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, ...  Find the sum of all the even-valued 
# terms in the sequence which do not exceed one million.
#

use bigint;

$ans = 0;

my ($a, $b) = (0, 1);
while($a < 1000000){
  if(($a % 2) == 0){ $ans+=$a;}
  ($a, $b) = ($b, $a+$b);
}

print $ans ."\n";
