#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> PII;

#define fir first
#define sec second
#define ep emplace
#define eb emplace_back

#define lowbit(x) ((x) & (-(x)))

inline int read() {
	int x = 0, f = 1; char ch = getchar();
	for (; !isdigit(ch); ch = getchar()) if (ch == '-') f = -1;
	for (; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + (ch ^ 48);
	return x * f;
}

const int N = 100010;

int n, a, b[N];
vector<int> res;

int main() {
	n = read(), a = read();
	int cnt = 0, ans = 0;
	for (int i = 1; i <= n; i ++ ) b[i] = read(), cnt += b[i];
	for (int i = 1; i <= n; i ++ ) res.eb(!b[(i % n) + 1] + !b[(i + n - 2) % n + 1] + !b[i]);
	sort(res.begin(), res.end(), greater<int>());
	for (int i = 0; i < n - a; i ++ ) ans += res[i];
	printf("%d\n", ans + cnt * 3);
	return 0;
}