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

int calc(const vector<int> &z,int day) {
	int sum = 0;
	for (int i=0;i<z.size();i++) {
		int saved = z[i]-day*2;
		if (saved <= 0) break;
		sum += max(1,saved-1);
		day += 2;
	}
	return sum;
}

int main() {
	ios_base::sync_with_stdio(0);
	int t;
	cin >> t;
	while (t--) {
		int n;
		cin >> n;
		string s;
		cin >> s;
		vector<int> z[2];
		int d=0,f=0;
		for (int i=0;i<n;i++) {
			if (s[i]=='0')
				d++;
			else {
				if (d>0) {
					z[f].push_back(d);
					d=0;
				}
				f=1;
			}
		}
		if (d>0) z[0].push_back(d);
		for (int i=0;i<2;i++)
			sort(z[i].begin(),z[i].end(),greater<int>());
		int ans = calc(z[1],0);
		int s0 = 0;
		for (int day=0;day<z[0].size();day++) {
			s0 += z[0][day]-day;
			ans = max(ans, s0 + calc(z[1],day+1));
		}
		cout << n-ans << endl;
	}
	return 0;
}