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#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define FOR(name, start, upper) for(int name = start; name < upper; ++name)

string tab;
vector <pair<int,int>> lenghts;

int main() 
{
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t;
    cin >> t;
    while(t--)
    {
        tab.clear(); lenghts.clear();
        int n = 0, sum = 0;
        tab.resize(n);
        cin >> n;
        FOR(i, 0, n)
        {
            cin >> tab[i];
            if(tab[i] == '1')
                sum++;
        }
        int p = 0; 
        FOR(i, 1, n)
        {
            if(tab[i] == '1' && tab[i-1] == '0')
            {
                pair<int,int> a;
                a.first = i-p; a.second = p;
                lenghts.push_back(a);
            }
            if(tab[i] == '0' && tab[i-1] == '1')
            {
                p = i;
            }
        }
        if(tab[n-1] == '0')
        {
            lenghts.push_back({n-p, p});
        }
        sort(lenghts.begin(), lenghts.end(), greater<pair<int,int>>());
        
        int i = 0;
        FOR(k, 0, lenghts.size())
        {
            int x = lenghts[k].first;
            if(lenghts[k].second == 0 || lenghts[k].second+x == n)
            {
                if(i >= x)
                {
                    sum += x;
                }
                else
                {
                    sum += i;
                }
            }
            else if(2*i >= x)
            {
                sum += x;
            }
            else
            {
                if(x-2*i > 1)
                sum += (2*i+1);
                if(x > 2)
                    i++;
            }
            i++;
        }
        cout << sum << "\n";
    }
}