#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int main()
{
    int a[100010],b[100010];
    int n;
    while(scanf("%d",&n),n)
    {
        memset(a,0,sizeof(a));
        memset(b,0,sizeof(b));
        int flag=0;
        for(int i=0;i<n;i++)
        {
            scanf("%d",&a[i]);
            if(a[i]<0)
            flag++;
        }
        int sum=0,k=0,kk=0;
        for(int i=0;i<n;i++)
        {
            if(a[i]>=0)
            {
                sum+=a[i];
                kk++;
                if(i==n-1)
                b[k++]=sum;
            }
            else
            {
                b[k++]=sum;
                sum=0;
            }
        }
        sort(b,b+k);
        if(b[k-1]>0&&b[k-2]==0&&kk>1)
        {
            printf("%d\n",b[k-1]);
            continue;
        }
        //cout<<k<<endl;
        //cout<<b[2]<<endl;
        //cout<<b[k-1]<<" "<<b[k-2]<<endl;
        if(b[k-1]==0)
        {
            sort(a,a+n);
            printf("%d\n",a[flag-1]+a[flag-2]);
        }
        else
        if(b[k-1]!=0&&b[k-2]==0)
        {
            sort(a,a+n);
            //cout<<a[flag-1]<<endl;
            printf("%d\n",b[k-1]+a[flag-1]);
        }
        else
        printf("%d\n",b[k-2]+b[k-1]);
    }
    return 0;
}