#include <bits/stdc++.h>

using namespace std;

#define all(x) (x).begin(), (x).end()
using ll = long long;
using vl = vector<ll>;

int calc(const string & s) {
    int ans = 0;
    for (char c : s) {
        if (c == '1') {
            ++ans;
        } else {
            return ans;
        }
    }
    assert(false);
}

void solve() {
    int n;
    cin >> n;
    string s;
    cin >> s;
    int ans = 0;
    for (int i = 0; i < n; ++i) {
        ans += s[i] == '1';
    }
    int pr = calc(s);
    reverse(all(s));
    int su = calc(s);
    cout << ans + min(pr, su) << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t;
    cin >> t;
    while (t--) {
        solve();
    }
}