#include <bits/stdc++.h>

using namespace std;
#define ll long long
#define pii pair<int, int>
#define ld long double
#define all(a) (a).begin(), (a).end()

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n, a;
    cin >> n >> a;

    vector<int> s(n);
    for (int i = 0; i < n; ++i) cin >> s[i];

    vector<int> ind(n);
    iota(all(ind), 0);
    sort(all(ind), [&](int i, int j) {
        return s[i] + s[(i - 1 + n) % n] + s[(i + 1) % n] > s[j] + s[(j - 1 + n) % n] + s[(j + 1) % n];
    });

    int res = 0;

    for (int i = 0; i < a; ++i) {
        int i1 = ind[i];
        res += s[i1] + s[(i1 - 1 + n) % n] + s[(i1 + 1) % n];
    }

    for (int i = a; i < n; ++i) {
        res += 3;
    }

    cout << res << '\n';

    return 0;
}