fn main() {
    let mut xx = String::new();
    std::io::Read::read_to_string(&mut std::io::stdin(), &mut xx).ok();
    let xx: Vec<&str> = xx.split_whitespace().collect();

    let k: usize = xx[1].parse().unwrap();

    let mut xx: Vec<i64> = xx[2..].iter().map(|&n| n.parse().unwrap()).collect();
    xx.sort_unstable();
    xx.reverse();

    let i = k.min(xx.iter().position(|&x| x <= 0).unwrap_or(xx.len()));
    let answer = xx[..i].iter().sum::<i64>();

    println!("{}", answer);
}