#include<iostream>
#include<vector>
using namespace std;
typedef long long ll;
//反算，减掉全1的数对
int main(){
    int n,a;
    cin>>n;
    ll rst=n*(n+1)/2;
    ll cnt1=0;
    for(int i=1;i<=n;i++){
        cin>>a;
        if(a==1) cnt1++;
        else{
            rst-=cnt1*(cnt1+1)/2;
            cnt1=0;
        }
    }
    rst-=cnt1*(cnt1+1)/2; //清除最后的连续1
    cout<<rst<<endl;
    return 0;
}