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

struct T {
	int len, cnt;
};

bool operator< (const T& a, const T& b) {
	return a.len*b.cnt < b.len*a.cnt;
}

void query() {
	int n;
	string s;
	cin >> n >> s;

	if(s == string(n,'0')) {
		cout << "0\n";
		return;
	}

	priority_queue<T> t;
	int len = 0, cnt = 1;

	for(char c : s)
		if(c == '0') len++;
		else {
			if(len > 0) t.push({len, cnt});
			len = 0, cnt = 2;
		}
	if(len > 0) t.push({len,1});

	int res = n;
	int tim = 0;
	while(!t.empty()) {
		auto x = t.top();
		t.pop();

		int left = x.len-tim*x.cnt;
		if(left > 0) {
			if(x.cnt == 1) res -= left;
			else {
				res--;
				x.cnt = 1;
				x.len -= tim+1;
				t.push(x);
			}
			tim++;
		}
	}

	cout << res << "\n";
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);

	int q;
	cin >> q;

	while(q--)
		query();

	return 0;
}