#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using i128 = __int128;
using u128 = unsigned __int128;
template <typename T>
void chkmax(T &x, const T &y) {
  if (x < y) x = y;
}
template <typename T>
void chkmin(T &x, const T &y) {
  if (y < x) x = y;
}
constexpr int MAXN = 1e5 + 10;
int n, a, b[MAXN], cnt[4];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cin >> n >> a;
  for (int i = 1, x; i <= n; ++i) {
    cin >> x;
    if (!x) {
      ++b[i];
      ++b[i == 1 ? n : i - 1];
      ++b[i == n ? 1 : i + 1];
    }
  }
  for (int i = 1; i <= n; ++i) ++cnt[b[i]];
  int ans = n * 3;
  for (int i = 0; i <= 3 && a; ++i) {
    int num = min(cnt[i], a);
    ans -= num * i;
    a -= num;
  }
  cout << ans << "\n";
  return 0;
}
/*
g++ M.cpp -o M -std=c++14 -O2 -Wall -Wextra -Wshadow -g -fsanitize=address,undefined
*/