use std::io::Read;

fn main() {
    let mut buf = String::new();
    std::io::stdin().read_to_string(&mut buf).unwrap();
    let mut iter = buf.split_whitespace();

    let n: usize = iter.next().unwrap().parse().unwrap();
    let k: usize = iter.next().unwrap().parse().unwrap();

    let mut a: Vec<i32> = Vec::with_capacity(n);
    for _ in 0..n {
        a.push(iter.next().unwrap().parse().unwrap());
    }

    a.sort_by(|x, y| y.cmp(x));

    let mut ans = 0;
    for i in 0..k {
        if a[i] < 0 { break; }
        ans += a[i];
    }

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