fn cycles() -> i64 {
    unsafe {
        use core::arch::x86_64::_rdtsc;
        _rdtsc()
    }
}

fn main() {
    let start = cycles();
    let mut sum = 0;
    for x in 0..1000 {
        if x % 3  == 0 {
            sum += x;
        } else if x % 5 == 0 {
            sum += x;
        }
    }
    let end = cycles();
    println!("Duration: {} cycles", end - start);
}