#include<bits/stdc++.h>
using namespace std;
inline void read(int &res){
	res=0;
	int f=1;
	char c=getchar();
	while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
	while(c>='0'&&c<='9')res=(res<<1)+(res<<3)+c-48,c=getchar();
	res*=f;
}
int n,m;
int a[100005],b[100005];
int main()
{
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	read(n);read(m);
	m=n-m;
	for(int i=1;i<=n;i++)read(a[i]);
	for(int i=2;i<n;i++)b[i]=(a[i-1]==0)+(a[i]==0)+(a[i+1]==0);
	b[1]=(a[n]==0)+(a[1]==0)+(a[2]==0);
	b[n]=(a[n]==0)+(a[1]==0)+(a[n-1]==0);
	sort(b+1,b+n+1);
	int ans=0;
	for(int i=1;i<=n;i++)if(a[i]==1)ans+=3;
	for(int i=n;i>=n-m+1;i--)ans+=b[i];
	cout<<ans;
	return 0;
}