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#include<bits/stdc++.h>

using namespace std;
const int N = 100 * 1000 + 7;
vector<pair<int, int>> v;

void Solve()
{
    int n, il, c, w;
    cin >> n;
    c = 0; il = 0; w = 0;
    for(int i = 1; i <= n; ++i)
    {
        char x;
        cin >> x;
        if(x == '1')
        {
            if(c == 0)
                v.push_back(make_pair(il * 2, 1));
            else
                v.push_back(make_pair(il, 2));
            c = 1; il = 0;
        }else
        {
            ++il;
        }
    }
    if(il != 0)
        v.push_back(make_pair(il * 2, 1));
    sort(v.begin(), v.end());
    reverse(v.begin(), v.end());
    il = 0;
    for(int i = 0; i < (int)v.size(); ++i)
    {
        if(il * 2 >= v[i].first)
            break;
        if(v[i].second == 1)
        {
            w += v[i].first / 2 - il;
            ++il;
        }else
        {
            w += v[i].first - il * 2 - 1;
            if(v[i].first - il * 2 == 1)
                ++w;
            il += 2;
        }
    }
    v.clear();
    cout << n - w << "\n";
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while(t--)
        Solve();

    return 0;
}