#include<bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin>>N;
  int A[202020];
  for(int i=1;i<=N;i++)cin>>A[i];
  long long answer=0;
  long long count=0;
  for(int i=1;i<=N;i++){
    if(A[i]==1)count++;
    else {
      answer=answer+(count*(count+1)/2);
      count=0;
    }
  }
  answer=answer+(count*(count+1)/2);
  cout<<(N*(N+1)/2)-answer;
  
}