#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
#define debug(p) for (auto i : p)cerr << i << " "; cerr << endl;
#define debugs(p) for (auto i : p)cerr << i.first << " " << i.second << endl;
typedef pair<int, int> pll;
string yes = "YES";
string no = "NO";
int lowbit(int x)
{
    return x & (-x);
}
void solve()
{
    int n;
    cin >> n;
    string s;
    cin >> s;
    s = '#' + s;
    vector<int>res(n + 1);
    int ans = 0;
    for (int i = 1; i <= n; i++)
    {
        if(res[i] && s[i] == '0')
        {
            ans++;
            for (int j = i; j <= n; j += lowbit(j))res[j]--;
        }   
        else if(res[i] == 0 && s[i] == '1')
        {
            ans++;
            for (int j = i; j <= n; j += lowbit(j))res[j]++;
        }
    }
    cout << ans << endl;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int T = 1;
    cin >> T;
    while(T--)
    {
        solve();
    }
}