#include<bits/stdc++.h>

using namespace std;

using i64 = long long ;

const i64 N = 1e5 + 10;

i64 n, m;
i64 a[N], cnt[4];
i64 cntsp;

void solve()
{
    cin >> n >> m;
    for(i64 i = 1;i <= n;i ++)
        {
            cin >> a[i];
            if (a[i]) cntsp ++;
        }
    a[n + 1] = a[1], a[0] = a[n];
    
    for(i64 i = 1;i <= n;i ++)
    {
        i64 t = 0;
        if (a[i] == 0) t ++;
        if (a[i - 1] == 0) t ++;
        if (a[i + 1] == 0) t ++;
        cnt[t] ++;
    }

    i64 ans = cntsp * 3;
    i64 dish = n - m;
    for(int i = 3;i ;i --)
    {
        ans += i * min(dish, cnt[i]);
        dish -= min(dish, cnt[i]);
    } 

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

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    solve();

    return 0;
}