#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll n; cin >> n;
    vector<int> a(n);
    for(int i=0;i<n;i++){
        cin >> a[i];
    }
    ll res=n*(n+1)/2;
    ll cnt=0;
    for(int i=0;i<n;i++){
        if(a[i]==0){
            res-=cnt*(cnt+1)/2;
            cnt=0;
        }
        else{
            cnt++;
        }
    }
    res-=cnt*(cnt+1)/2;
    cout << res << endl;
}