#include<bits/stdc++.h>
using namespace std;
using ll = long long;
// #define rep(i,m,n) for(int i=m; i<n; ++i)
// #define repl(i,m,n) for(ll i=m; i<n; ++i)
#define rep(i,m,n) for(ll i=m; i<n; ++i)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

int main(){
    ll N;
    cin >> N;
    vector<ll> A(N);
    rep(i, 0, N) cin >> A[i];

    vector<ll> nonzero;
    ll cnt = 0LL;
    rep(i, 0, N){
        if(A[i] == 0LL){
            if(cnt != 0LL){
                nonzero.push_back(cnt);
                cnt = 0LL;
            }
        }else{
            cnt++;
        }
    }
    if(cnt != 0LL) nonzero.push_back(cnt);

    ll ans = (N+1LL) * N / 2LL;
    for(ll x : nonzero){
        ans -= (x+1LL) * x / 2LL;
    }
    cout << ans << endl;
    
    return 0;
}