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

struct row {
    int leng;
    int sids;
};

vector<struct row> A;

bool comp(struct row a, struct row b) {
    return a.leng*2/a.sids > b.leng*2/b.sids;
}

int main() {
    int q;
    scanf("%d", &q);
    for (int i=0;i<q;i++) {
        A.clear();
        int n;
        scanf("%d", &n);
        char c;
        int sds = 1;
        int leng = 0;
        for (int j=0;j<n;j++) {
            scanf(" %c", &c);
            if (c == '1') {
                if (leng > 0) {
                    A.push_back(row{leng,sds});
                }
                sds = 2;
                leng = 0;
            }
            else leng++;
        }
        if (leng > 0) A.push_back(row{leng,1});
        sort(A.begin(), A.end(), comp);
        int tp = 0;
        int k, s = 0;
        for (int i=0;i<A.size();i++) {
            if (A[i].sids == 1) {
                k = A[i].leng-tp;
                if (k <= 0) break;
                s += k;
                tp++;
            }
            else {
                k = A[i].leng-2*tp;
                if (k <= 0) break;
                if (k == 1) s++;
                else s += k-1;
                tp += 2;
            }
        }
        printf("%d\n", n-s);
    }
}