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