#include<bits/stdc++.h>
using namespace std;
#ifdef LOCAL_JUDGE
#include<local_debug>
#else
#define debug(...) 1
#endif
#define ls (p<<1)
#define rs (p<<1|1)
#define pb push_back
#define int long long
#define eb emplace_back
#define lowbit(x) (x&-x)
#define rint register int
#define alls(a) a.begin(),a.end()
#define mem(a,b) memset(a,b,sizeof a)
typedef long long ll;
typedef __int128 i128;
typedef long double ld;
typedef unsigned long long ull;
typedef pair<int,int> pii;
bool ST;
const int inf=0x3f3f3f3f;
const ll INF=1e18;
template<typename T>
void read(T &x){
x=0;int f=1;char c=getchar();
while(!isdigit(c)){if(c=='-') f=-1;c=getchar();}
while(isdigit(c)){x=x*10+c-'0';c=getchar();}
x*=f;
}
template<typename T,typename ... Args>
void read(T &x, Args &... y){read(x);read(y...);}
namespace Mr_Az{
const int N=3e5+8;
int T=1;
int n,k,m,ans,cnt;
bool f=0;
int a[N],b[N];
bool vis[N];
set<int> s;
set<pii> q;
inline int abs(int x){return x<0?-x:x;}
inline void solve(){
read(n,k);
for(rint i=1;i<=n;i++) read(a[i]);a[0]=-1;
for(rint i=1;i<=n;i++){
f|=(a[i]>=0);
if(f){
m+=!((a[i-1]<0&&a[i]<0)||(a[i-1]>=0&&a[i]>=0));
b[m]+=a[i];
}
}
if(a[n]<0) m--;
b[0]=b[m+1]=0;
for(rint i=1;i<=m;i++){
cerr<<b[i]<<" ";
if(b[i]>=0) cnt++;
q.insert({abs(b[i]),i});
s.insert(i);
}cerr<<endl;
while(cnt>k){
cerr<<cnt<<" "<<k<<endl;
auto [x,i]=*q.begin();
auto it=s.lower_bound(i),pre=it,nxt=it;
pre--;nxt++;
if(b[i]<0&&(it==s.begin()||nxt==s.end())){
s.erase(it);
q.erase(q.begin());
continue;
}
vector<int> t;t.clear();
if(b[i]>=0) cnt--;
if(it!=s.begin()){
b[i]+=b[*pre];
t.pb(*pre);
}
if(nxt!=s.end()){
b[i]+=b[*nxt];
t.pb(*nxt);
}
q.erase(q.begin());
for(auto xx:t){
if(b[xx]>=0) cnt--;
s.erase(s.find(xx));
auto it1=q.find({abs(b[xx]),xx});
if(it1!=q.end()) q.erase(it1);
}
q.insert({abs(b[i]),i});
if(b[i]>=0) cnt++;
}
while(q.size()){
auto [x,i]=*(q.begin());q.erase(q.begin());
if(b[i]>=0) ans+=b[i];
}
end:
printf("%lld\n",ans);
return ;
}
inline void mian(){if(!T) read(T);while(T--) solve();}
}
bool ED;
signed main(){
// freopen(".in","r",stdin);
// freopen(".out","w",stdout);
auto st=clock();
Mr_Az::mian();
auto ed=clock();
cerr<<endl;
cerr<<"Time: "<<ed-st<<" ms\n";
cerr<<"Memory: "<<abs(&ST-&ED)/1024.0/1024.0<<" MB\n";
return 0;
}
