#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
using ll = long long;
using ull = unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)


int main(){
  int N; cin >> N;
  vector<int> A(N); rep(i,N) cin >> A[i];
  ll ans = (ll)N * (N+1) / 2;
  ll c = 0;
  for(auto a : A){
    if(a == 1) c++;
    else{ ans -= c * (c+1) / 2; c = 0; }
  }
  ans -= c * (c+1) / 2;
  cout << ans << "\n";
  return 0;
}


struct ios_do_not_sync{
  ios_do_not_sync(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
  }
} ios_do_not_sync_instance;