#include <bits/stdc++.h>
using namespace std;

int main() {
    size_t n, k;
    cin >> n >> k;
    vector<long long> a(n);
    for (auto& ai : a) cin >> ai;
    if (k == 0) {
        auto calc = [a](long long x) {
            long long res = 0;
            for (auto ai : a) res -= abs(x - ai);
            return res;
        };
        cout << min(calc(a.front()), calc(a.back())) << '\n';
        return 0;
    }
    vector<long long> s(1);
    partial_sum(a.begin(), a.end(), back_inserter(s));
    long long ans = LLONG_MAX;
    size_t l = 0, r = k - 1;
    for (size_t i = 0; i < n; ++i) {
        while (r + 1 < n && a[i] - a[l] > a[r + 1] - a[i]) l++, r++;
        long long now = (n - 2 * l - 2 * r + 2 * i) * a[i] + 2 * (s[l] + s[r + 1] - s[i + 1]) - s[0] - s[n];
        ans = min(ans, now);
    }
    cout << ans << '\n';
}