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#include <iostream> 
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <queue>

using namespace std;

void solve() {
    int n;
    cin >> n;
    priority_queue<pair<int, bool>> q;
    int ln = 0;
    char c, p = 0;
    bool first = true;
    for(int i = 0; i < n; i++) {
        cin >> c;
        if (c == '1') {
            if (ln > 0) {
                if (first) {
                    ln *= 2;
                }
                q.push(make_pair(ln, first));
            }
            first = false;
            ln = 0;
        }
        else if (c == '0') {
            ln++;
        }
        
        if (i == n-1 && ln > 0) {
            ln *= 2;
            q.push(make_pair(ln, true));
        }
    }
    int dest = 0;
    int wyn = 0;
    int cln = 0;
    while(!q.empty()) {
        pair<int, bool> p = q.top();
        q.pop();
        int cw = 0;
        if (p.second == true) {
            cw = (p.first / 2) - dest;
            dest++;
        } else {
            cw = p.first - (dest * 2);
            if (cw > 1) {
                cw -= 1;
            }
            dest += 2;
        }
        if (cw > 0) {
            wyn += cw;
        }
    }
    cout << n - wyn << endl;
}

int main() {
    ios::sync_with_stdio(false);
    int t;
    cin >> t;
    while(t--) solve();
}