#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 10;
int n, a;
bool st[N];
int num[4];

inline int gl(int x) {return x == 0 ? n - 1 : x - 1;}
inline int gr(int x) {return x == n - 1 ? 0 : x + 1;}

void solve()
{
    cin >> n >> a;
    int res = 3 * n;
    for (int i = 0; i < n; ++i) cin >> st[i];
    int count = 0;
    count += st[0];
    count += st[1];
    count += st[n - 1];
    num[count]++;
    count -= st[n - 1];

    for (int i = 1; a && i < n; ++i)
    {
        count += st[gr(i)];
        num[count]++;
        count -= st[gl(i)];
    }

    // for (int i = 0; i <= 3; ++i) cout << num[i] << ' '; cout << '\n';
    a -= min(a, num[3]);

    res -= min(a, num[2]);
    a -= min(a, num[2]);

    res -= 2 * min(a, num[1]);
    a -= min(a, num[1]);

    res -= 3 * a;

    cout << res;
}

int main(void)
{
    ios::sync_with_stdio(false); std::cin.tie(nullptr); std::cout.tie(nullptr);
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}