use std::{i64::MAX, io::stdin};

fn main() {
    let stdin = stdin();
    let mut stdin = stdin.lines().map(Result::unwrap);
    let n = stdin.next().unwrap().parse::<usize>().unwrap();
    let mut a = stdin
        .next()
        .unwrap()
        .split_whitespace()
        .map(|x| x.parse::<i64>().unwrap())
        .collect::<Vec<_>>();
    a.sort();
    let mut dp = vec![MAX; n + 1];
    dp[0] = 0;
    for i in 0..=n {
        if i == 1 {
            continue;
        }
        for k in 2..=3 {
            if i + k <= n {
                change_min!(&mut dp[i + k], dp[i] + a[i + k - 1] - a[i]);
            }
        }
    }
    let ans = dp[n];
    println!("{}", ans);
}

// cmpmore {{{
#[allow(dead_code)]
mod cmpmore {
    pub fn change_min<T: PartialOrd>(lhs: &mut T, rhs: T) {
        if *lhs > rhs {
            *lhs = rhs;
        }
    }
    pub fn change_max<T: PartialOrd>(lhs: &mut T, rhs: T) {
        if *lhs < rhs {
            *lhs = rhs;
        }
    }
    #[macro_export]
    macro_rules! change_min {
        ($lhs:expr, $rhs:expr) => {
            let rhs = $rhs;
            let lhs = $lhs;
            $crate::cmpmore::change_min(lhs, rhs);
        };
    }
    #[macro_export]
    macro_rules! change_max {
        ($lhs:expr, $rhs:expr) => {
            let rhs = $rhs;
            let lhs = $lhs;
            $crate::cmpmore::change_max(lhs, rhs);
        };
    }
    pub trait CmpMore: PartialOrd + Sized {
        fn change_min(&mut self, rhs: Self) {
            change_min(self, rhs)
        }
        fn change_max(&mut self, rhs: Self) {
            change_max(self, rhs)
        }
    }
    impl<T: PartialOrd + Sized> CmpMore for T {}
}
// }}}