427ApoliceRecruits.cpp

#include <iostream>
using namespace std;

int main()
{
    int n, e;
    int p = 0, c = 0;
    cin >> n;

    for(int i = 0; i < n; i++)
    {
        cin >> e;
        if(e == -1)
        {
            if(p > 0)
                p--;
            else
                c++;
        }
        else
            p += e;
    }

    cout << c << endl;
    return 0;
}