#include<bits/stdc++.h>
#define int long long int
using namespace std;

void solve(){
	
    int n;
    cin>>n;
    while(true){
        int a[n];
        for(int i=0;i<n;i++) cin>>a[i];
        vector<pair<int,int> > buy;
        vector<pair<int,int> > sell;
        for(int i=0;i<n;i++){
            if(a[i]>0) buy.push_back({a[i],i});
            else sell.push_back({a[i],i});
        }
        int ans = 0;
        int i=0,j=0;
        while(i<buy.size() and j<sell.size()){
            int x = min(buy[i].first,-sell[j].first);
            buy[i].first -= x;
            sell[j].first += x;
            int diff = abs(buy[i].second - sell[j].second);
            ans += (x * diff);
            if(buy[i].first == 0) i++;
            if(sell[j].first == 0) j++;
        }
        cout<<ans<<endl;
        cin>>n;
        if(n==0) break;
    }
}

int32_t main()
{
	ios_base::sync_with_stdio(false);
    cin.tie(NULL);
	
	solve();
	
	
	return 0;
}