#![allow(unused_imports)]

fn main() {
    input! {
        n: usize,
        mut a: [i64; n],
    }
    a.sort();
    let y = -a[..n / 2].iter().sum::<i64>();
    let x = a[n / 2..].iter().sum::<i64>();
    println!("{}", x - y);
}

use proconio::{input, marker::*};
use std::{cmp::Reverse, collections::*};

#[macro_export]
macro_rules! chmax {
    ($a:expr, $b:expr) => {{
        let tmp = $b;
        if $a < tmp {
            $a = tmp;
            true
        } else {
            false
        }
    }};
}

#[macro_export]
macro_rules! chmin {
    ($a:expr, $b:expr) => {{
        let tmp = $b;
        if $a > tmp {
            $a = tmp;
            true
        } else {
            false
        }
    }};
}

#[macro_export]
/// mvec![]
macro_rules! mvec {
    ($val:expr; ()) => {
        $val
    };
    ($val:expr; ($size:expr $(,$rest:expr)*)) => {
        vec![mvec![$val; ($($rest),*)]; $size]
    };
}