#include<bits/stdc++.h>
//#define int long long
#define fr(i,a,b) for(int i(a),end##i(b);i<=end##i;i++)
#define fd(i,a,b) for(int i(a),end##i(b);i>=end##i;i--)
#define mk make_pair
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
using namespace std;
int n,m;
const int maxn=1e5+5;
int a[maxn],cnt[10];
signed main(){
#ifdef pig
	freopen("pig.in","r",stdin);
	freopen("pig.out","w",stdout);
#endif
	cin>>n>>m;
	fr(i,1,n){
		scanf("%d",&a[i]);
		a[i]^=1;
	}
	a[0]=a[n];a[n+1]=a[1];
	fr(i,1,n)cnt[a[i]+a[i-1]+a[i+1]]++;
	int ans=3*n;
	fr(i,0,3){
		if(m>=cnt[i]){
			m-=cnt[i];
			ans-=cnt[i]*i;
		}else {
			ans-=m*i;
			break;
		}
	}
	cout<<ans;
	return 0;
}