#include <stdio.h>
#include <string.h>

#include <algorithm>

using namespace std;

typedef long long LL;
constexpr int N = 100005;

int n, m, b[N];

int main() {
	scanf("%d%d", &n, &m);
	m = n - m;
	int cnt = 0;
	for (int i = 0, x; i < n; ++i) {
		scanf("%d", &x);
		if (x) {
			cnt += 1;
		} else {
			b[i] += 1;
			b[i + 1] += 1;
			b[i + 2] += 1;
		}
	}
	b[0] += b[n];
	b[1] += b[n + 1];
	sort(b, b + n), reverse(b, b + n);
	int res = 0;
	for (int i = 0; i < m; ++i) {
		res += b[i];
	}
	printf("%d\n", res + cnt * 3);
	return 0;
}