#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N;
    cin >> N;
    vector<int> A(N), B(N, 0);
    rep(i, 0, N) cin >> A[i];
    rep(i, 2, N) {
        if (A[N - i] != A[N - i - 1]) B[N - i - 1] = B[N - i] + 1;
    }
    ll ans = 0;
    rep(i, 0, N - 1) {
        if (A[i] == 1) ans += 1 + B[i];
    }
    cout << ans << endl;
    //rep(i, 0, N) cout << B[i] << " "; cout << endl;
}