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

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 1 << 17;
string c;
VI g[N];

int ans = 0;
void dfs(int v){
	
	int c1 = 0;
	for(int to : g[v]){
		dfs(to);
		c1 += c[to] == '1';
	}
	if(c1 == 1 && c[v] == '0')
		ans++;
	if(c1 == 0 && c[v] == '1')
		ans++;
}


void solve(){
	int n;
	cin >> n >> c;
	ans = 0;
	FOR(i, 1, n + 1){
		int ni = i + (i & (-i));
		if(ni > n){
			dfs(i - 1);
			continue;
		}
		g[ni - 1].PB(i - 1);
	}
	
	cout << ans << "\n";
	FOR(i, 0, n)
		g[i].clear();
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin >> t;
	while(t--)
		solve();
		
	return 0;
}