#include <iostream>
#include <algorithm>
#include <vector>
#include <set>

using namespace std;

using i64 = long long;

const int N = 100010;

int n, a;
int b[N], c[N];

int main() {
    cin.tie(0), cout.tie(0)->sync_with_stdio(false);
    cin >> n >> a;
    for (int i = 1; i <= n; i++) {
        cin >> b[i];
        if (b[i] == 1) {
            c[i]++;
            c[i % n + 1]++;
            c[(i + n - 2) % n + 1]++;
        }
    }
    int res = 0;
    sort(c + 1, c + n + 1, greater<>());
    for (int i = 1; i <= a; i++) {
        res += c[i];
    }
    cout << res + 3 * (n - a);
    return 0;
}