fn main() {
    let mut nk = String::new();
    std::io::stdin().read_line(&mut nk).ok();
    let nk: Vec<usize> = nk.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nk[0];
    let k = nk[1];
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<isize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let k = (n-k).min(n-1);
    let mut summary = (0..n).map(|i| a[i] - a[0]).sum::<isize>();
    let mut rights = (0..n).rev().take(k).collect::<Vec<_>>();
    summary -= rights.iter().map(|&i| a[i] - a[0]).sum::<isize>() * 2;
    let mut lidx = 0usize;
    let mut result = summary;
    for i in 1..n {
        let diff = a[i] - a[i-1];
        summary += i as isize * diff;
        summary -= lidx as isize * 2 * diff;
        summary -= (n  - i) as isize * diff;
        summary += rights.len() as isize * 2 * diff;
        while lidx < n && !rights.is_empty() {
            let rval = rights[rights.len()-1];
            if a[i] - a[lidx] <= a[rval] - a[i] {
                break;
            } else {
                summary -= (a[i] - a[lidx]) * 2;
                summary += (a[rval] - a[i]) * 2;
                lidx += 1;
                rights.pop();
            }
        }
        result = result.min(summary);
    }
    println!("{}", result);
}