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#include<bits/stdc++.h>
using namespace std;

int t;

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> t;
    for (int xyz = 1; xyz <= t; xyz++)
    {
        int n;
        string s;
        cin >> n >> s;
        vector <int> v;

        int num1 = 0, last1 = 0;
        for (int i = 0; i < n; i++)
        {
            if (s[i] == '0')
                continue;
            if (num1 == 0)
                v.push_back(i);
            else{
                v.push_back((i - last1) / 2);
                v.push_back((i - last1 - 1) / 2);
            }
            num1++;
            last1 = i;
        }
        if (last1 != 0)
            v.push_back(n - last1 - 1);
        
        if (num1 == 0){
            cout << "0\n";
            continue;
        }
        sort(v.begin(), v.end());
        reverse(v.begin(), v.end());

        int res = 0;
        for (int i = 0; i < v.size(); i++){
            res += max(0, v[i] - i);
        }
        cout << (n - res) << "\n";
    }
    return 0;
}