#include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct block {
ll val;
block *prev, *next;
block(ll val): val(val) {
prev = next = nullptr;
}
};
using blockpt = block*;
struct compare {
bool operator () (const blockpt &x,
const blockpt &y) const {
return abs(x->val) != abs(y->val) ?
abs(x->val) < abs(y->val) : x < y;
}
};
const int N = 3e5 + 5;
set <block*, compare> blocks;
int a[N]; block *b[N];
bool sign(const int &x) {
return x <= 0 ? 0 : 1;
}
int main() {
cin.tie(0)->sync_with_stdio(0);
int n, k, m = 0, p = 0;
cin >> n >> k;
for (int i = 1; i <= n; cin >> a[i++]);
for (int i = 1; i <= n; ) {
int j = i; ll sum = 0;
while (j <= n && sign(a[i])
== sign(a[j])) sum += a[j++];
if (sum > 0 || m > 0)
b[m++] = new block(sum);
i = j; p += sum > 0;
}
if (m > 0 && b[m - 1]->val < 0) m--;
for (int i = 0; i < m; i++)
blocks.insert(b[i]);
for (int i = 1; i < m; i++) {
b[i]->prev = b[i - 1];
b[i - 1]->next = b[i];
}
while (p > k && blocks.size()) {
blockpt it = *blocks.begin();
blocks.erase(it);
if (it->val > 0) p--;
if (it->prev) {
blocks.erase(it->prev);
if (it->prev->val > 0) p--;
it->val += it->prev->val;
it->prev = it->prev->prev;
if (it->prev)
it->prev->next = it;
}
if (it->next) {
blocks.erase(it->next);
if (it->next->val > 0) p--;
it->val += it->next->val;
it->next = it->next->next;
if (it->next)
it->next->prev = it;
}
if (it->val <= 0) {
if (!it->prev)
it->next->prev = 0;
else if (!it->next)
it->prev->next = 0;
else blocks.insert(it);
}
else {
blocks.insert(it); p++;
}
}
ll res = 0;
for (auto it : blocks)
res += max(0ll, it->val);
cout << res << '\n';
}
