#include <bits/stdc++.h>
#define int long long
#define x first
#define y second
#define bug(X) cout << "bug:# " << X << endl
#define bug2(f, X) cout << "bug:# " << f << " " << X << endl
#define bug3(i, j, G) cout << "bug:# " << i << ' ' << j << ' ' << G << endl
#define endl '\n'
using namespace std;
const int mod = 998244353;
const int N = 10 + 5e5;
void _();
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    // cin >> t;
    while (t--)
        _();
    return 0;
}

struct Node
{
    int a, f, w, con;
};
void _()
{
    int n, k;
    cin >> n >> k;
    vector<Node> node(n + 1);
    for (int i = 1; i <= n; i++)
    {
        cin >> node[i].a;
        node[i].f = i;
    }
    for (int i = 1; i <= n; i++)
        if (node[i].a == 0)
        {
            node[i].w++;
            node[i % n + 1].w++;
            node[(i + n - 2) % n + 1].w++;
        }
    sort(node.begin() + 1, node.end(), [](Node &e1, Node &e2)
         { return e1.w > e2.w; });
    int left = n - k;
    for (int i = 1; i <= n; i++)
        if (left)
            node[i].con++, left--;
    sort(node.begin(), node.end(), [](Node &e1, Node &e2)
         { return e1.f < e2.f; });
    int res = 0;
    for (int i = 1; i <= n; i++)
        if (node[i].a == 1)
            res += 3;
        else
        {
            res += node[i].con != 0;
            res += node[i % n + 1].con != 0;
            res += node[(i + n - 2) % n + 1].con != 0;
        }
    cout << res << endl;
}