#include<bits/stdc++.h>
#define ph push_back
#define pp pop_back
#define ff first
#define ss second
#define endl '\n'
#define int long long
using namespace std;

const int N=1e5+5;
int n,gg,a[N],b[N];

signed main()
{
//	freopen("temp.in","r",stdin);
//	freopen("temp.out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin>>n>>gg;
	for(int i=0;i<n;i++) cin>>a[i];
	for(int i=0;i<n;i++)
	{
		if(!a[(i-1+n)%n]) b[i]++;
		if(!a[(i+1)%n]) b[i]++;
		if(!a[i]) b[i]++;
	}
	sort(b,b+n);
	int s=0;
	for(int i=1;i<=gg;i++) s+=b[i];
	cout<<3*n-s;
	return 0;
}