#include<bits/stdc++.h>

#define ll long long
#define int long long
#define mk make_pair
#define fi first
#define se second

using namespace std;

inline int read(){
    int x=0,f=1;char c=getchar();
    for(;(c<'0'||c>'9');c=getchar()){if(c=='-')f=-1;}
    for(;(c>='0'&&c<='9');c=getchar())x=x*10+(c&15);
    return x*f;
}

const int mod=998244353;
int ksm(int x,int y,int p=mod){
    int ans=1;
    for(int i=y;i;i>>=1,x=1ll*x*x%p)if(i&1)ans=1ll*ans*x%p;
    return ans%p;
}
int inv(int x,int p=mod){return ksm(x,p-2,p)%p;}
mt19937 rnd(time(0));
int randint(int l,int r){return rnd()%(r-l+1)+l;}
void add(int &x,int v){x+=v;if(x>=mod)x-=mod;}
void Mod(int &x){if(x>=mod)x-=mod;}

void cmax(int &x,int v){x=max(x,v);}
void cmin(int &x,int v){x=min(x,v);}

signed main(void){

#ifndef ONLINE_JUDGE
    freopen("in.in","r",stdin);
#endif     

    int tt=read();while(tt--){
        int n=read();
        vector<int>can(n+1,0);
        for(int i=1;i<=n;i++){
            char c=getchar();while(c!='0'&&c!='1')c=getchar();
            can[i]=(c=='1');
        }
        int cnt=0,ans=0;
        for(int i=n;i>=1;i--){
            if(!can[i]){cnt++;continue;}
            if(cnt>=1)cnt--,ans+=i;
            else cnt++;
        }
        cout<<ans<<'\n';
    }

    return 0;
}