#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define int long long
const int MOD = 1e9 + 7;
const int INF = 1e15;
const int N = 1e6;
int n, m, k, a, b, c, d, h, l, r, q, u, v, x, y;
vector<int> arr(N);
vector<int> all;
void build() {
for(int i = 0; i<n; i++) {
l = i;
h = 0;
if(arr[i] < 0) {
while(l<n && arr[l] < 0) {
h += arr[l];
l++;
}
}
else {
while(l<n && arr[l] >= 0) {
h += arr[l];
l++;
}
}
all.pb(h);
i = l-1;
}
}
void combine() {
while(x > k) {
bool found = false;
for(int i = 0; i<all.size(); i++) {
if(all[i] >= 0) continue;
if(abs(all[i]) <= (min(all[i+1], all[i-1]))) {
all[i-1] += all[i+1]+all[i];
all.erase(all.begin()+i, all.begin()+i+2);
found = true;
x--;
break;
}
}
if(!found) break;
}
}
void solve() {
cin >> n >> k;
for(int i = 0; i<n; i++) {
cin >> arr[i];
}
build();
x = 0;
h = 0;
for(auto j : all) {
// cout << j << " ";
if(j >= 0) {
h += j;
x++;
}
}
// cout << "\n";
if(x <= k) {
cout << h;
return;
}
if(all[0] < 0) all.erase(all.begin());
if(all.back() < 0) all.pop_back();
// for(auto j : all) cout << j << " ";
// cout << "\n";
combine();
// for(auto j : all) cout << j << " ";
// cout << "\n";
vector<int> pos;
c = 0;
for(auto j : all) {
if(j >= 0) {
pos.pb(j);
}
}
sort(pos.rbegin(), pos.rend());
c = 0;
for(int i = 0; i<k; i++) {
c += pos[i];
}
cout << c;
}
int32_t main() {
ios::sync_with_stdio(false);
cout.tie(0); cin.tie(0);
int tc = 1;
// cin >> tc;
while(tc--) {
solve();
cout << "\n";
}
return 0;
}
