#include<bits/stdc++.h>
#define poly vector<int>
#define IOS ios::sync_with_stdio(false)
#define ll long long
#define mp make_pair
#define mt make_tuple
#define pa pair < int,int >
#define fi first
#define se second
#define inf 1e18
#define mod 998244353
#define int ll
#define N 100005
using namespace std;
int n,m,a[N],cnt[5];
inline int work(int &x,int &y)
{
	int t=min(x,y);
	x-=t,y-=t;
	return t;
}
void BellaKira()
{
	cin>>n>>m;
	int X=0,Y=0;
	for (int i=0;i<n;i++)
		cin>>a[i],X+=a[i];
	int ans=0;
	int x=m,y=n-m;
	for (int i=0;i<n;i++)
	{
		int now=0;
		for (int j=-1;j<=1;j++)
			now+=(a[(i+j+n)%n]);
		cnt[now]++;
	}
	ans+=work(cnt[0],y)*3;
	
	ans+=work(cnt[1],y)*2;
	
	ans+=work(cnt[2],y)*1;
	// cout<<"?"<<ans<<" "<<X<<'\n';
	cout<<ans+X*3<<'\n';
}
signed main()
{
	IOS;
	cin.tie(0);
	int T=1;
	while (T--)
	{
		BellaKira();
	}
}