#include<iostream>
using namespace std;

int main(){
	bool flag[5000] = {false};
	int n, in[5000];
	long long ans, tmp = 0ll;
	
	while(true){
		cin >> n;
		if(n == 0)
			break;

		for(int i = 0; i < n; ++i){
			cin >> in[i];
			if(in[i] > 0)
				flag[i] = true;
		}//input

		for(int i = 0; i < n; ++i){
			for(int j = i; j < n; ++j){
				if(flag[i] && flag[j]){
					for(int k = i; k <= j; ++k)
						tmp += in[k];
					if(tmp > ans){
						ans = tmp; 
						tmp = 0ll;
					}	
					else
						tmp = 0ll;
				}
			}
		}
		
		cout << ans << endl;//output
		
		ans = 0ll;
		for(int i = 0; i < n; ++i)
			flag[i] = false;//intialize
	
	}
	return 0;
}