#include<iostream>

#include<cstdio>

#define MIN -0x3f3f3f3f;

using namespace std;

int a[],lmax[],rmax[],n;

int main()

{

    while(scanf("%d",&n) && n)

    {

        lmax[] = MIN;

        rmax[n+] = MIN;

        for(int i = ;i <= n;i++)    scanf("%d",&a[i]);

        int sum = ;

        for(int i = ;i <= n;i++)

        {

            sum += a[i];

            if(lmax[i-] < sum)    lmax[i] = sum;

            else    lmax[i] = lmax[i-];

            if(sum < )    sum = ;

        }

        sum = ;

        for(int i = n;i >= ;i--)

        {

            sum += a[i];

            if(rmax[i+] < sum)    rmax[i] = sum;

            else    rmax[i] = rmax[i+];

            if(sum < )    sum = ;

        }

        int maxx = MIN;

        for(int i = ;i < n;i++)    maxx = max(maxx,lmax[i]+rmax[i+]);

        printf("%d\n",maxx);

    }

    return ;

}