#include<bits/stdc++.h>

using namespace std;

#define int long long

const int N = 1e5+10;


void solve(){
	int n,a,x;
	cin >> n >> a;
	int b[n + 10] = {};
	int ans = 0;
	for (int i = 1;i <= n;i ++){
		cin >> x;
		if (x == 0){
			b[i % n + 1] ++;
			b[i] ++;
			b[(i + n - 2) % n + 1] ++;
		}else{
			ans += 3;
		}
	}
	sort(b + 1,b + n + 1);
	a = n - a;
	for (int i = n;i >= 1;i --){
		if (a){
			ans += b[i];
			a --;
		}else break;
	}
	cout << ans << "\n";
}

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	solve();
}