SUMSEQ0

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

int c(int k, int n) {
    int a = 1, b = 1;
    for (int i = 1; i <= k; i++) {
        b *= i;
    }
    for (int i = n - k + 1; i <= n; i++) {
        a *= i;
    }
    return a / b;
}

int n, a[100005], p[100005], cnt = 0;
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    // freopen("SUMSEQ0.inp", "r", stdin);
    // freopen("SUMSEQ0.out", "w", stdout);
    map<int, int> m;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        if (i == 0)
            p[i] = a[i];
        else
            p[i] = p[i - 1] + a[i];
        m[p[i]]++;
    }

    for (auto &i : m) {
        if (i.first == 0) {
            cnt += i.second;
            if (i.second >= 2)
                cnt += c(2, i.second);
        } else if (i.second >= 2)
            cnt += c(2, i.second);
    }
    cout << cnt;
    return 0;
}