//太暴力了吧
#include<cstdio>
#include<iostream>
using namespace std;
int n,a[10005];
int main(){
while(~scanf("%d",&n))
{
for(int i=0;i<n;++i)
scanf("%d",a+i);
int ans=0;
while(1)
{
int f=1;
for(int i=0;i<n;++i)
if(a[i]<0)
{
++ans;
f=0;
a[(i+1)%n]+=a[i];
a[(i+n-1)%n]+=a[i];
a[i]=-a[i];
}
if(f) break;
}
printf("%d\n",ans);
}
return 0;
}