#include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct Edge
{
    ll to;
    ll cost;
};
using Graph = vector<vector<Edge>>;
using P = pair<ll, ll>;
#define mp make_pair
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
#define ALL(v) (v).begin(), v.end()
ll MOD = 998244353;
const ll nmax = 8;
const ll INF = 1e10;
const int MAX = 510000;
bool graph[nmax][nmax];
long long fac[MAX], finv[MAX], inv[MAX];
void Case(int i) { printf("Case #%d: ", i); }
void COMinit()
{
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++)
    {
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

ll COM(int n, int k)
{
    if (n < k)
        return 0;
    if (n < 0 || k < 0)
        return 0;

    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

vector<vector<ll>> dist = vector<vector<ll>>(nmax, vector<ll>(nmax, INF));
void warshall_floyd(ll n)
{
    for (size_t i = 0; i < n; i++)
    {
        for (size_t j = 0; j < n; j++)
        {
            for (size_t k = 0; k < n; k++)
            {
                dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
            }
        }
    }
}

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b)
{
    ll g = gcd(a, b);
    return a / g * b;
}

ll mulMod(ll a, ll b)
{
    return (((a % MOD) * (b % MOD)) % MOD);
}

ll powMod(ll a, ll p)
{
    if (p == 0)
    {
        return 1;
    }
    else if (p % 2 == 0)
    {
        ll half = powMod(a, p / 2);
        return mulMod(half, half);
    }
    else
    {
        return mulMod(powMod(a, p - 1), a);
    }
}

ll ceil(ll a, ll b)
{
    return (a + b - 1) / b;
}

bool isPrime(ll N)
{
    for (int i = 2; i * i <= N; i++)
    {
        if (N % i == 0)
            return false;
    }
    return true;
}

ll cntbit(ll i)
{
    if (i == 0)
        return 0;

    ll ret = 0;
    i++;
    while (i != 0)
    {
        i = i >> 1;
        ret++;
    }
    return ret - 1;
}

ll getSize(ll a)
{
    ll ret = 0;
    while (a != 0)
    {
        ret++;
        a /= 10;
    }
    return ret;
}

vector<pair<long long, long long>> prime_factorize(long long N)
{
    vector<pair<long long, long long>> res;
    for (long long a = 2; a * a <= N; ++a)
    {
        if (N % a != 0)
            continue;
        long long ex = 0;

        while (N % a == 0)
        {
            ++ex;
            N /= a;
        }

        res.push_back({a, ex});
    }

    if (N != 1)
        res.push_back({N, 1});
    return res;
}
ll dp[3][3];

ll dx[4] = {-1, 0, 0, 1};
ll dy[4] = {0, -1, 1, 0};
int main()
{
    ll N;
    cin >> N;
    vector<ll> a(N);
    for (int i = 0; i < N; i++)
    {
        cin >> a[i];
    }

    bool isOne = false;
    ll sum = 0;
    ll cnt = 0;
    for (int i = 0; i < N; i++)
    {
        if (a[i] == 1)
        {
            cnt++;
        }
        else
        {
            sum += cnt * (cnt + 1) / 2;
            cnt = 0;
        }
    }
    sum += cnt * (cnt + 1) / 2;

    cout << N * (N + 1) / 2 - sum << endl;

    return 0;
}