#include <bits/stdc++.h>

#ifdef LOCAL
#include "/home/kmiao/codes/debugtemplate.cpp"
#else
#define debug(...)
#endif

using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()

#define pb push_back
#define mp make_pair
#define endl '\n'

using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using pii = pair<int, int>;

const int MOD = 1e9 + 7;
const ll INF = (ll)1e18;

class HashedString {
  private:
	// change M and B if you want
	static const ll M = (1LL << 61) - 1;
	static const ll B;

	// pow[i] contains B^i % M
	static vector<ll> pow;

	// p_hash[i] is the hash of the first i characters of the given string
	vector<ll> p_hash;

	__int128 mul(ll a, ll b) { return (__int128)a * b; }
	ll mod_mul(ll a, ll b) { return mul(a, b) % M; }

  public:
	HashedString(const string &s) : p_hash(s.size() + 1) {
		while (pow.size() < s.size()) { pow.push_back(mod_mul(pow.back(), B)); }
		p_hash[0] = 0;
		for (int i = 0; i < s.size(); i++) {
			p_hash[i + 1] = (mul(p_hash[i], B) + s[i]) % M;
		}
	}

	ll get_hash(int start, int end) {
		ll raw_val =
		    p_hash[end + 1] - mod_mul(p_hash[start], pow[end - start + 1]);
		return (raw_val + M) % M;
	}
};
mt19937 RNG((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
vector<ll> HashedString::pow = {1};
const ll HashedString::B = uniform_int_distribution<ll>(0, M - 1)(RNG);


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

    int grp = 0;
    int ans = 0;
    for (int i = 0; i < n; i++) {
        if (s[i] == '0') continue;
        grp++;
        int j = i;
        while (j < n && s[j] == '1') {
            j++;
            ans++;
        }
        i = j-1;
    }
    if (grp > 1) {
        cout << ans+1 << endl;
    } else {
        cout << ans << endl;
    }
}

int main() {
    // read read read
    cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);

    int t = 1;
    cin >> t;
    
    while (t--) {
        solve();
    }

    return 0;
    // read the thing at the bottom
}

/* stuff you should look for
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
	* DON'T GET STUCK ON ONE APPROACH
*/