#include<iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    long long res = 0, count = 0;
    for (int i = 0; i < n; i++) {
        int a;
        cin >> a;
        if (a == 1) count++;
        if (a == 0 || i == n - 1) {
            res += (long long)count * (count + 1) / 2;
            count = 0;
        }
    }
    res = (long long)n * (n + 1) / 2 - res;
    cout << res << endl;
    return 0;
}