#include <iostream>
#include <queue>
#include <stack>
#include <vector>
#include <deque>
#include <set>
#include <map>
#include <unordered_map>
#include <cassert>
#include <algorithm>
#include <cmath>
#include <random>
#include <ctime>
#include <cstdlib>
#include <chrono>

using namespace std;

void solve() {
  int n, a;
  cin >> n >> a;

  int na = n - a;

  vector<int> v(2 * n + 1);
  for (int i = 1; i <= n; ++i) {
    cin >> v[i];
    v[n + i] = v[i];
  }

  v[0] = v[n];


  vector<int> ds(n + 1, 1);
  priority_queue<pair<int, int>> s;
  for (int i = 1; i <= n; ++i) {
    int x = (v[i - 1] == 0) + (v[i] == 0) + (v[i + 1] == 0);
    s.push({x, i});
  }

  for (int i = 1; i <= na; ++i) {
    int p = s.top().second;
    ds[p] = 0;
    s.pop();
  }

  ds[0] = ds[n];
  ds[n + 1] = ds[1];

  int ans = 0;
  for (int i = 1; i <= n; ++i) {
    if (v[i] == 1) {
      ans += 3;
    } else {
      ans += (ds[i - 1] == 0) + (ds[i] == 0) + (ds[i + 1] == 0);
    }
  }

  cout << ans << "\n";
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);

  int t = 1;
  while (t--)
    solve();

  return 0;
}