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

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int T;
    cin >> T;
    while (T--) {
        int N;
        string S;
        cin >> N >> S;
        
        vector<int> segments;
        int count = 0;
        
        // Collect all segments of consecutive '1's
        for (int i = 0; i < N; ++i) {
            if (S[i] == '1') {
                ++count;
            } else {
                if (count > 0) {
                    segments.push_back(count);
                }
                count = 0;
            }
        }
        // Add the last segment if it ends with '1'
        if (count > 0) {
            segments.push_back(count);
        }

        // Sort segments in descending order to simulate optimal play
        sort(segments.rbegin(), segments.rend());

        // Roy's optimal score: sum the lengths of every other segment (1st, 3rd, etc.)
        int max_consecutive_1s = 0;
        for (int i = 0; i < segments.size(); i += 2) {
            max_consecutive_1s += segments[i];
        }

        cout << max_consecutive_1s << endl;
    }
    return 0;
}