/*
* @Author: zxxzy
* @Date:   2023-06-26 23:15:27
*/
#include <iostream>
#include <algorithm>
#include <cstring>
#include <bitset>
#include <set>
#include <cmath>
#include <vector>
#include <map>
//#define int long long
#define space ' '
#define endl '\n'
#define de(x) cout<<"** "<<x<<" **"<<endl;
#define N 200005
using namespace std;
using ll=long long;
const int mod=998244353;
const int INF=0x3f3f3f3f;
const double eps=1e-6;


signed main(){
    #ifdef LOCAL
        freopen("D:\\code2023\\test\\input.txt", "r", stdin);
        freopen("D:\\code2023\\test\\output.txt", "w", stdout);
    #endif
    std::ios::sync_with_stdio(false);
    cin.tie(0);
    int n,a;
    cin>>n>>a;
    vector<int> b(n);
    for(int i=0;i<n;i++){
        cin>>b[i];
    }
    auto f=[&](int x){
        return(x+1)%n;
    };
    auto g=[&](int x){
        return (x-1+n)%n;
    };
    int ans=0;
    int ss[4]={0,0,0,0};
    for(int i=0;i<n;i++){
        int sum=b[i]+b[f(i)]+b[g(i)];
        sum=3-sum;
        ss[sum]++;
    };
    for(int i=0;i<n;i++){
        if(b[i]){
            ans+=3;

        }
    };
    a=n-a;
    // for(int i=0;i<4;i++){
    //     cout<<ss[i]<<endl;
    // }
    // de(ans)
    // while(a){
        while(a&&ss[3]){
            ans+=3;
            a--;
            ss[3]--;
        }
        while(a&&ss[2]){
            ans+=2;
            a--;
            ss[2]--;
        }
        while(a&&ss[1]){
            ans++;
            a--;
            ss[1]--;
        }
    // }
    cout<<ans<<endl;
    return 0;
}