#include <iostream>
#include <fstream>

using namespace std;

#define MIN(a,b) (a > b ? b : a)
#define MAX(a,b) (a > b ? a : b)

typedef long long LL;

LL a[100000];

int maxPos(int l, int r)
{
	LL m = 0;
	int x=a[0];
	for(int i = l; i < r; ++i)
	{
		if(m < a[i])
		{
			m = a[i];
			x = i;
		}
	}

	return x;
}

int main()
{
	ifstream fin("gergovia.in");


	while(1)
	{
		int n;
		fin >> n;
		if(n == 0)
			break;

		LL total = 0;
		for(int i = 0; i < n; ++i)
		{
			fin >> a[i];
			total += a[i];
		}

		LL work = 0;
		while(1)
		{
			int p = maxPos(0, n);
			if(a[p] == 0)
				break;
			int r = 0, l = 0;
			while(1)
			{
				if(a[p+r] < 0)
				{
					LL mi = MIN(a[p], -a[p+r]);
					a[p+r] += mi;
					a[p] -= mi;
					work += r * mi;
					break;
				}
				if(a[p-l] < 0)
				{
					LL mi = MIN(a[p], -a[p-l]);
					a[p-l] += mi;
					a[p] -= mi;
					work += l * mi;
					break;
				}
			
				
				if(p - l > 0)
					l++;
				else if(r == n)
					break;
				if(p + r < n)
					r++;
				else if(l == 0)
					break;
			}
			
		}
		cout << work << endl;
	}



	return 0;
}