#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
#define debug(x) cout<<#x<<": "<<x<<endl
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
using ll=long long;
using ull=unsigned long long;
#define int long long
void solve(){
    int n,a;
    cin>>n>>a;
    vector<int> w(n),g(n);
    for(int i=0;i<n;i++)
        cin>>w[i];
    int res=0;
    for(int i=0;i<n;i++){
        if(w[i]==0){
            g[i]++;
            g[(i-1+n)%n]++;
            g[(i+1)%n]++;
        }
        else
            res+=3;
    }
    sort(g.begin(),g.end());
    reverse(g.begin(),g.end());
    for(int i=0;i<n-a;i++)
        res+=g[i];
    cout<<res<<endl;
}
signed main(){
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    int t=1;
    while(t--){
        solve();
    }
}