use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        n: usize,
        k: usize,
        a: [i8; n],
    }

    println!("{}", output(solve(k, a)))
}

fn solve(k: usize, mut a: Vec<i8>) -> i16 {
    a.sort_unstable_by_key(|&a| std::cmp::Reverse(a));
    match a[0] >= 0 {
        true => a
            .into_iter()
            .take(k)
            .take_while(|&a| a >= 0)
            .map(|a| a as i16)
            .sum(),
        false => a[0] as i16,
    }
}

fn output(ans: i16) -> i16 {
    ans
}