#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5; 

int n, x, id[N]; 
int a[N]; 
bool vis[N]; 

int pre(int x) { return x == 1 ? n : x - 1; }
int nxt(int x) { return x == n ? 1 : x + 1; }

int main(void) {
    ios::sync_with_stdio(0); 
    cin >> n >> x; x = n - x; 
    for (int i = 1; i <= n; ++i) cin >> a[i], id[i] = i; 
    sort(id + 1, id + n + 1, [&](int x, int y) { return (!a[x]) + (!a[pre(x)]) + (!a[nxt(x)]) > (!a[y]) + (!a[pre(y)]) + (!a[nxt(y)]); }); 
    for (int i = 1; i <= x; ++i) vis[id[i]] = 1; 
    int ans = 0; 
    for (int i = 1; i <= n; ++i)
        if (a[i]) ans += 3; 
        else ans += vis[pre(i)] + vis[i] + vis[nxt(i)]; 
    cout << ans << "\n"; 
    return 0;
}