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#include <cstdio>
#include <vector>
#include <utility>
#include <algorithm>

constexpr int N = 100*1000+10;

char cities[N];

int main() {
    int t;
    scanf("%d", &t);
    while (t > 0) {
        int n;
        scanf("%d %s", &n, cities);
        std::vector<std::pair<int, int>> healthy;
        int i = 0;
        int current = 0;
        while (i < n && cities[i] == '0') {
            i++;
            current++;
        }
        if (current > 0) {
            healthy.emplace_back(2 * current, current);
        }
        i++;
        current = 0;
        while (i < n) {
            while (i < n && cities[i] == '0') {
                i++;
                current++;
            }
            if (i < n) {
                if (current > 0) {
                    healthy.emplace_back(current, current);
                }
                current = 0;
                i++;
            }
        }
        if (current > 0) {
            healthy.emplace_back(2 * current, current);
        }
        std::sort(healthy.begin(), healthy.end(), std::greater<std::pair<int, int>>());
        int result = 0;
        int turn = 0;
        for (i = 0; i < healthy.size(); ++i) {
            if (healthy[i].first <= turn * 2) {
                break;
            }
            if (healthy[i].first == healthy[i].second) {
                if (healthy[i].second == 2 * turn + 1) {
                    result++;
                    turn++;
                } else {
                    result += healthy[i].second - (2 * turn + 1);
                    turn += 2;
                }
            } else {
                result += healthy[i].second - turn;
                turn++;
            }
        }
        printf("%d\n", n - result);
        t--;
    }
}