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