use proconio::input;

fn main() {
    input! {
        n: usize,
        mut c: [i64; n]
    }
    c.sort_unstable();
    let (l, r) = (c[0], c[n - 1]);
    let ans = if l * r >= 0 {
        l.abs().max(r.abs()) * 2
    } else {
        (l.abs() + r.abs()) * 2
    };
    println!("{}", ans);
}