#include<bits/stdc++.h>
#define int long long
#define double long double
#define lowbit(x) x&(-x)
#define fastios ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define endl '\n'
#define el puts("")
#define udm unordered_map<int,int>
#define set_0(a) memset(&a,0,sizeof(a))
#define set_unint(a) memset(&a,-1,sizeof(a))
using namespace std;
//define_var
const int M=2e5+9,inf=1e18;
int b[M];
//define_var
//function_begin
int read()
{
	int x=0,f=1;
	char c=getchar();
	while(c<'0'||c>'9'){if(c=='-') f=-1;c=getchar();}
	while(c>='0'&&c<='9') x=x*10+c-'0',c=getchar();
	return x*f;
}
void write(int x)
{
	if(x<0) putchar('-'),x=-x;
	if(x>9) write(x/10);
	putchar(x%10+'0');
}
bool cmp(int a,int b)
{
	return a>b;
}
//function_end
//solve_begin
void solve()
{
	vector<int> v;
	int n,a,ans=0;
	cin>>n>>a;
	for(int i=1;i<=n;i++)
		cin>>b[i],ans+=b[i]*3;
	for(int i=1;i<=n;i++)
	{
		int n1,n2,n3,cs=0;
		n2=i,n1=i-1,n3=i+1;
		if(n1<1) n1=n;
		if(n3>n) n3=1;
		if(b[n1]==0) cs++;
		if(b[n2]==0) cs++;
		if(b[n3]==0) cs++;
		v.push_back(cs);
	}
	sort(v.begin(),v.end(),cmp);
	for(int i=0,ps=1;i<v.size()&&ps<=n-a;i++,ps++)
		ans+=v[i];
	cout<<ans<<endl;
}
//solve_end
//main_begin
signed main()
{
	fastios
	int T=1;
//	cin>>T;
	while(T--)
		solve();
}
//main_end