#include "bits/stdc++.h"
using namespace std;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, k;
cin>>n>>k;
k--;
deque<long long> a(n);
long long r = 0;
for(int i = 0; i < n; i++) cin>>a[i];
while(!a.empty() and a[0] < 0){
a.pop_front();
}
while(!a.empty() and a.back() < 0){
a.pop_back();
}
vector< pair<long long, pair<int, int> > > Borrar;
long long Suma = 0;
a.push_back(0);
n = a.size();
for(int i = 0; i < n; i++){
if(a[i] < 0){
if(Suma == 0) Borrar.push_back({0LL, {i, -2}});
Suma += a[i];
} else if(Suma != 0){
Borrar.back().first = Suma;
Borrar.back().second.second = i;
Suma = 0;
}
}
sort(Borrar.begin(), Borrar.end());
for(int i = 0; i < k and i < Borrar.size(); i++){
for(; Borrar[i].second.first < Borrar[i].second.second; Borrar[i].second.first++){
a[Borrar[i].second.first] = -0;
}
}
Suma = 0;
for(auto E: a){
Suma += E;
Suma = max(0LL, Suma);
r = max(Suma, r);
}
cout<<r;
return 0;
}
