#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).ok();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().ok().unwrap()
    };
}

#[allow(unused_imports)]
use std::collections::{HashMap, HashSet, VecDeque};

fn main() {
    setup! { mut input: SplitWhitespace };

    let n: usize = parse_next!(input);
    let mut y: Vec<i64> = (0..n).map(|_| parse_next!(input)).collect();

    y.sort();

    macro_rules! sum_with_baseline {
        ($vec:expr, $baseline:expr) => {
            $vec.iter()
                .fold(0, |acc, val| acc + (val - $baseline).abs())
        };
    }

    let ans = (|| {
        let baseline = match n % 2 == 0 {
            true => y[(n / 2) - 1],
            false => y[((n + 1) / 2) - 1],
        };
        sum_with_baseline!(y, baseline)
    })();

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