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// clang-format off
#include <bits/stdc++.h>

using namespace std;

#define ALL(x) (x).begin(), (x).end()

template<class C> void mini(C &a5, C b5) { a5 = min(a5, b5); }
template<class C> void maxi(C &a5, C b5) { a5 = max(a5, b5); }

#ifdef LOCAL
const bool debug = true;
#else
const bool debug = false;
#define cerr if (true) {} else cout
#endif
// clang-format on

#define int long long
#define double long double

const int INF = 1e18;
const int mod = 1e9 + 7;

struct Algo {
	int n, res;
	string s;

	Algo() {
		cin >> n >> s;
		vector<int> v;
		
		res = 0;
		
		{
			int i = 0, j;
			while (i < n) {
				if (s[i] == '1') {
					i++;
					res++;
					continue;
				}
				
				j = i;
				while (j < n && s[j] == '0') {
					j++;
				}
				
				v.push_back(j - i);
				if (i == 0 || j == n) v.back() *= 2;
				else v.push_back(v.back());

				i = j;
			}
		}
		
		sort(ALL(v));
		reverse(ALL(v));
		res *= 2;
		
		for (int i = 0; i < (int)v.size(); i++) {
			int x = v[i];
			
			if (i * 2 >= x) {
				res += x;
				continue;
			}
			
			res += 2 * i;
		}
		
		cout << res / 2 << "\n";
	}
};

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    int t;
    cin >> t;
    while (t--) {
		Algo p;
	}
    
    return 0;
}/*
3
8
00110100
10
1001000010
4
0000
*/