#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int n,m;
int sum[N],a[N],vis[N];
int solve(){
	int ans=3*n;
	if(vis[0]>=m)return ans;
	m-=vis[0];
	if(vis[1]>=m){
		ans-=m;
		return ans;
	}
	ans-=vis[1];m-=vis[1];
	if(vis[2]>=m){
		ans-=(2*m);
		return ans;
	}
	ans-=(vis[2]*2);m-=vis[2];
	ans-=(3*m);
	return ans;
}
int main(){
	scanf("%d%d",&n,&m);//m个辣菜 
	for(int i=1;i<=n;i++){
		scanf("%d",&a[i]);
		a[i]=1-a[i];
	}
	a[0]=a[n];a[n+1]=a[1];
	for(int i=1;i<=n;i++)sum[i]=a[i-1]+a[i]+a[i+1];//表示如果为辣会损失多少 
	for(int i=1;i<=n;i++)vis[sum[i]]++;
	cout<<solve()<<endl;
	return 0;
}