fn main() {
    // first();
    second();

}
fn first() {
    let mut sum = 0;
    for x in 0..1000 {
        if x%3 == 0 || x%5 ==0 {
            sum = sum + x;
        }
    }
    println!("{}",sum);
}
fn second() {
    let f1 = 1;
    let f2 = 1;
    let mut sum = 0;
    let mut curr = f1 + f2;
    let mut prev = f2;
    while curr < 4_000_000 {
        if curr % 2 == 0 {
            sum = sum + curr;
        }
        let temp = curr;
        curr = curr + prev;
        prev = temp;
    }
    println!("{}", sum);
}