
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <memory>
#include <string>

#include <algorithm>
#include <complex>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <vector>

using namespace std;

#ifdef _MSC_VER
#define __typeof__ decltype
#endif

#define ITER(c)         __typeof__((c).begin())
#define FOREACH(it, c)  for (ITER(c) it=(c).begin(); it != (c).end(); ++it)
#define RITER(c)        __typeof__((c).rbegin())
#define RFOREACH(it, c) for (RITER(c) it=(c).rbegin(); it != (c).rend(); ++it)
#define REP(i, n)       REPEAT(i, 0, n)
#define REPEAT(i, k, n) for (int i = (k); i < (n); ++i)
#define REVREP(i, n)    for (int i = ((n)-1); i >= 0; --i)
#define FIND(c, n)      std::find((c).begin(), (c).end(), (n));
#define BSEARCH(c, n)   std::binary_search((c).begin(), (c).end(), (n))
#define LLPOW(p1,p2)    ((ll)pow((double)(p1), (int)p2))
#define ESIZEOF(A)      (sizeof(A)/sizeof((A)[0]))
#define MIN(p1,p2)      (((p1)<(p2))?(p1):(p2))
#define MAX(p1,p2)      (((p1)>(p2))?(p1):(p2))
#define CIN_NO_SYNC     do { cin.tie(0); ios_base::sync_with_stdio(false); } while(0)
#define GETSTR(p)       fgets((p), sizeof(p), stdin)
#define CHOMP(p)        do{ char *_q = (p) + strlen(p)-1; if(*_q == '\n') *_q = 0; } while(0)

int main(){
    int n;
    while(cin >> n, n){
        list<int> v;
        int p = 0;
        REP(i, n){
            int in;
            cin >> in;
            if((p <= 0 && in < 0) || p >= 0 && in > 0 || in == 0){
                p += in;
            } else {
                v.push_back(p);
                p = in;
            }
        }
        v.push_back(p);

        while(v.size() >= 3){
            //FOREACH(it, v){ cout << *it << ", ";} cout << endl;
            bool f = false;
            FOREACH(it, v){
                int p1 = *it;
                if(p1 < 0) continue;
                ITER(v) it2 = it; it2++;
                if(it2 == v.end()) break;
                int p2 = *it2;
                ITER(v) it3 = it2; it3++;
                if(it3 == v.end()) break;
                int p3 = *it3;

                int sum = p1 + p2 + p3;
                if(sum > p1 && sum > p3){
                    v.erase(it2);
                    v.erase(it3);
                    *it += (p2+p3);
                    f = true;
                    break;
                }
            }
            if(!f) break;
        }

        int max = INT_MIN;
        FOREACH(it, v){
            if(max < *it) max = *it;
        }
        cout << max << endl;
    }
    return 0;
}