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#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef pair<ld, ld> PLD;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef vector<VII> VVII;
typedef vector<PLL> VLL;
typedef vector<VLL> VVLL;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef vector<bool> VB;

template <class T, class G>
ostream &operator<<(ostream &os, const pair<T, G> &para) {
  os << para.first << " " << para.second;
  return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  for (const T &el : vec)
    os << el << " ";
  return os;
}
template <class T> ostream &operator<<(ostream &os, const set<T> &vec) {
  for (const T &el : vec)
    os << el << " ";
  return os;
}

#define REP(i, j) for (int i = 0; i < j; i++)
#define REP1(i, j) for (int i = 1; i < j; i++)
#define FOREACH(el, n) for (auto &el : n)
#define LAST(x) (x[(int)x.size() - 1])
#define pb push_back
#define pf push_front
#define st first
#define nd second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sp ' '
#define ent '\n'

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);

  int t = 1;
  cin >> t;
  while (t--) {
    int n;
    string s;
    cin >> n >> s;
    bool fd = false;
    priority_queue<pair<PII, int>> pq;
    int cnt = 0;
    REP(i, n) {
      if (s[i] == '0') {
        cnt++;
      } else {
        if (i == 0)
          fd = true;
        if (cnt == 0)
          continue;
        if (fd) {
          pq.push({{(cnt + 1) / 2, -2}, cnt});
        } else {
          pq.push({{cnt, -1}, 0});
          fd = true;
        }
        cnt = 0;
      }
    }
    if (cnt > 0) {
      pq.push({{cnt, -1}, 0});
    }
    if (!fd) {
      cout << 0 << ent;
      continue;
    }
    int saved = 0;
    int days_passed = 0;
    while (!pq.empty()) {
      auto v = pq.top();
      pq.pop();
      // cout << v << ent;
      if (v.st.st <= days_passed)
        break;
      if (v.st.nd == -2) {
        int oryg_len = v.nd;
        v.st.nd = -1;
        v.nd = 0;
        v.st.st = oryg_len - days_passed - 1;
        pq.push(v);
        saved++;
      } else {
        saved += v.st.st - days_passed;
      }
      days_passed++;
    }
    cout << n - saved << ent;
  }

  return 0;
}