#include <bits/stdc++.h>
using namespace std;
#define int long long
#define fi first
#define se second
#define ll long long
#define pb push_back
#define db(val) "[" #val " = " << (val) << "] "
const ll mod = 1e9 + 7;
const int maxn = 3e5 + 4;
const int INF = 1e9;
using T = pair<int,int>;
int n, k, a[maxn], par[maxn], Rank[maxn];
priority_queue<T, vector<T>, greater<T>> pq;
vector<int> myVec;
set<int> ms;
struct DisjointSet {
DisjointSet(int n) {
for (int i = 1; i <= n; i++) {
par[i] = i, Rank[i] = myVec[i - 1];
pq.push({abs(Rank[i]), i});
ms.insert(i);
}
}
int find(int x) {
if (x != par[x]) par[x] = find(par[x]);
return par[x];
}
bool join(int u, int v) {
if (u == v) return 0;
ms.erase(v);
Rank[u] += Rank[v];
par[v] = u;
return 1;
}
};
void init() {
while (Rank[*ms.begin()] < 0)
ms.erase(*ms.begin());
while (Rank[*ms.rbegin()] < 0)
ms.erase(*ms.rbegin());
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
//freopen(".INP", "r", stdin);
//freopen(".OUT", "w", stdout);
cin >> n >> k;
for (int i = 1; i <= n; i++)
cin >> a[i];
int cur = 0, cnt = 0;
int L = 1, R = n;
while (a[L] <= 0) L++;
while (a[R] <= 0) R--;
int flag = (a[L] > 0 ? 1 : -1);
for (int i = L; i <= R + 1; i++) {
if (a[i] * flag < 0 || i == R + 1) {
if (cur > 0)
cnt++;
myVec.pb(cur);
cur = 0;
flag = (a[i] > 0 ? 1 : -1);
}
cur += a[i];
}
n = myVec.size();
DisjointSet Dsu(n);
while (cnt > k) {
int cur, x; tie(cur, x) = pq.top(); pq.pop();
if (ms.find(x) == ms.end()) continue;
auto lo = ms.lower_bound(x);
auto hi = ms.upper_bound(x);
int u = (lo == ms.begin() ? x : *(--lo));
int v = (hi == ms.end() ? x : *hi);
u = Dsu.find(u); v = Dsu.find(v);
int pre = (Rank[u] > 0 && u != x) + (Rank[v] > 0 && v != x) + (Rank[x] > 0);
Dsu.join(x, u);
Dsu.join(x, v);
pq.push({abs(Rank[x]), x});
int suf = Rank[u] > 0;
cnt -= (pre - suf);
init();
}
int res = 0;
for (auto i : ms)
if (Rank[i] > 0) res += Rank[i];
cout << res;
}
