// https://www.facebook.com/abhi.sensharma/posts/1241788872853419
// Subscribed by Abhishek Sharma

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int [] arr = new int [n];
        for(int i = 0; i < n; i ++) {
            arr[i] = sc.nextInt();
        }

        int count = 0, sum = 0;
        for(int i = 0; i < n; i ++) {
            for(int j = i; j < n; j ++) {
                sum += arr[j];
                if(sum < 0) count ++;  
            }
            sum = 0;
        }
        System.out.println(count);
    }
}