#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <map>
#include <set>
#include <cmath>
#include <bitset>
#include <cassert>
#include <numeric>

using namespace std;
typedef long long ll;

void solve()
{
    int n, a;
    cin >> n >> a;
    int b[n + 10];
    for (int i = 0; i < n; i ++)
        cin >> b[i];
    bool st[n + 10] = {0};

    int ans = count(b, b + n, 1) * 3;
    a = n - a;

    for (int i = 0; i < n; i ++)
    {
        if (!a) break;
        int cnt = (b[(i - 1 + n) % n] == 0) + (b[i] == 0) + (b[(i + 1) % n] == 0);
        if (cnt == 3)
        {
            a --;
            st[i] = true;
            ans += cnt;
        }
    }

    for (int i = 0; i < n; i ++)
    {
        if (!a) break;
        if (st[i]) continue;
        int cnt = (b[(i - 1 + n) % n] == 0) + (b[i] == 0) + (b[(i + 1) % n] == 0);
        if (cnt == 2)
        {
            a --;
            st[i] = true;
            ans += cnt;
        }
    }

    for (int i = 0; i < n; i ++)
    {
        if (!a) break;
        if (st[i]) continue;
        int cnt = (b[(i - 1 + n) % n] == 0) + (b[i] == 0) + (b[(i + 1) % n] == 0);
        if (cnt == 1)
        {
            a --;
            st[i] = true;
            ans += cnt;
        }
    }

    cout << ans << '\n';
}

int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int tt = 1;
    // cin >> tt;
    while (tt --)
    {
        solve();
    }
    return 0;
}