#include<bits/stdc++.h>
using namespace std;
#define int long long
#define INF 0x3f3f3f3f3f3f3f3f
#define pii pair<int,int>
#define fi first
#define se second
#define all(_a) _a.begin(), _a.end()
const int N=1e5+10;
int a[N],id[N],b[N],s[N];

bool cmp(int x,int y){
    if(b[x]==b[y]) return x<y;
    else return b[x]>b[y];
}

void solve(){
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++) cin>>a[i];
    for(int i=1;i<=n;i++){
        if(a[i]==1){
            b[i]++;
            b[i%n+1]++;
            b[(i+n-2)%n+1]++;
        }
        else{
              b[i]--;
            b[i%n+1]--;
            b[(i+n-2)%n+1]--;
        }
        id[i]=i;
    }
    sort(id+1,id+1+n,cmp);
    int ans=0;
    for(int i=1;i<=m;i++) s[id[i]]=1;
    for(int i=1;i<=n;i++){
        if(a[i]==1){
            ans+=3;
            continue;
        }
        else{
            if(b[s[i]]==a[i]) ans++;
            if(b[s[i%n+1]]==a[i]) ans++;
            if(b[s[(i+n-2)%n+1]]==a[i]) ans++;
        }
    }
    cout<<ans<<endl;
}
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    cout << setiosflags(ios::fixed) << setprecision(15);
    int T;
    T=1;
    //cin>>T;
    while(T--)solve();
    return 0;
}