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#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ull  unsigned long long
#define s second
#define f first
#define mp make_pair
const long long  maxN = 5e5+7;

bool cmp(long long  a, long long  b)
{
    return  a>b;
}

void solve()
{
    long long  n;
    cin>>n;
    char c,last='1';
    vector<long long >vec,rst;
    bool ok=0;
    long long  zer=0;
    for (long long  i = 0; i < n; i++)
    {
        cin>>c;
        if(c=='0')zer++;
        else
        { 
            
            if(last=='0')
            {
                if(zer<=2 && ok) rst.push_back(zer);
                else if(ok)vec.push_back(zer-1);
            }
            if(!ok) rst.push_back(zer);
            ok=1;

            zer=0;
        }
        last=c;
    }
    rst.push_back(zer);
    long long  k=0,ans=0;
    sort(vec.begin(),vec.end(),cmp);
    sort(rst.begin(),rst.end(),cmp);
    for (long long  i = 0; i < vec.size(); i++)
    {
        if((vec[i]-k*2)<=0) break;
        ans+=vec[i]-k*2;
        k+=2;
    }
    for (long long  i = 0; i < rst.size(); i++)
    {
        if((rst[i]-k)<=0)break;
        ans+=rst[i]-k;
        k++;
    
    }
    
    cout<<n-ans<<"\n";

}

int  main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    long long  t;
    cin>>t;
    while(t--)solve();

}