#include "bits/stdc++.h"
#include <array>
using namespace std;

using ll = long long;
using pii = pair<int, int>;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	int n, a;
	cin >> n >> a;
	vector<int> b(n);
	for (int i = 0; i < n; i++) {
		cin >> b[i];
	}
	int ans = (n - a) * 3;
	
	array<int, 4> cntf = array<int, 4>();
	for (int i = 0; i < n; i++) {
		int prev = (i - 1 + n) % n;
		int nxt = (i + 1) % n;
		int cnt = 0;
		if (b[prev]) ++cnt;
		if (b[i]) ++cnt;
		if (b[nxt]) ++cnt;
		cntf[cnt]++;
	}
	for (int i = 3; i >= 1; i--) {
		ans += min(a, cntf[i]) * i;
		a -= min(a, cntf[i]);
	}
	cout << ans << "\n";
}