#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
const int INF = 1e9;
const int NEGINF = 0xC0C0C0C0;
const int NULO = -1;
const double EPS = 1e-10;
const ll mod = 1e9 + 7;
const ll inf = 1e17;
int dy[] = {-1, 0, 1, 0};
int dx[] = {0, 1, 0, -1};
vector<int> sort_cyclic_shifts(string const &s) {
  int n = s.size();
  const int alphabet = 256;
  vector<int> p(n), c(n), cnt(max(alphabet, n), 0);
  for (int i = 0; i < n; i++) {
    cnt[s[i]]++;
  }
  for (int i = 1; i < alphabet; i++) {
    cnt[i] += cnt[i - 1];
  }
  for (int i = 0; i < n; i++) {
    p[--cnt[s[i]]] = i;
  }
  c[p[0]] = 0;
  int classes = 1;
  for (int i = 1; i < n; i++) {
    if (s[p[i]] != s[p[i - 1]]) {
      classes++;
    }
    c[p[i]] = classes - 1;
  }
  vector<int> pn(n), cn(n);
  for (int h = 0; (1 << h) < n; ++h) {
    for (int i = 0; i < n; i++) {
      pn[i] = p[i] - (1 << h);
      if (pn[i] < 0) {
        pn[i] += n;
      }
    }
    fill(cnt.begin(), cnt.begin() + classes, 0);
    for (int i = 0; i < n; i++) {
      cnt[c[pn[i]]]++;
    }
    for (int i = 1; i < classes; i++) {
      cnt[i] += cnt[i - 1];
    }
    for (int i = n - 1; i >= 0; i--) {
      p[--cnt[c[pn[i]]]] = pn[i];
    }
    cn[p[0]] = 0;
    classes = 1;
    for (int i = 1; i < n; i++) {
      pair<int, int> cur = {c[p[i]], c[(p[i] + (1 << h)) % n]};
      pair<int, int> prev = {c[p[i - 1]], c[(p[i - 1] + (1 << h)) % n]};
      if (cur != prev) {
        ++classes;
      }
      cn[p[i]] = classes - 1;
    }
    c.swap(cn);
  }
  return p;
}
vector<int> suffix_array_construction(string s) {
  s += "$";
  vector<int> sorted_shifts = sort_cyclic_shifts(s);
  sorted_shifts.erase(sorted_shifts.begin());
  return sorted_shifts;
}
vector<int> lcp_construction(string const &s, vector<int> const &p) {
  int n = s.size();
  vector<int> rank(n, 0);
  for (int i = 0; i < n; i++) {
    rank[p[i]] = i;
  }
  int k = 0;
  vector<int> lcp(n - 1, 0);
  for (int i = 0; i < n; i++) {
    if (rank[i] == n - 1) {
      k = 0;
      continue;
    }
    int j = p[rank[i] + 1];
    while (i + k < n && j + k < n && s[i + k] == s[j + k]) {
      k++;
    }
    lcp[rank[i]] = k;
    if (k) {
      k--;
    }
  }
  return lcp;
}
const int maxn = 5e3 + 10;
ll dp[maxn];
vector<int> p;
vector<int> lcp;
int n;
ll solve(int i) {
  int l = 1e9;
  ll &ans = dp[i];
  if (ans != -1) {
    return ans;
  }
  ans = 0;
  for (int j = i + 1; j < n; j++) {
    l = min(l, lcp[j - 1]);
    if (p[j] > p[i]) {
      ans = max(ans, solve(j) + (n - p[j] - l));
    }
  }
  return ans;
}
void solveTestCase() {
  cin >> n;
  string s;
  cin >> s;
  p = suffix_array_construction(s);
  lcp = lcp_construction(s, p);
  memset(dp, -1, sizeof(dp));
  ll ans = 0;
  for (int i = 0; i < n; i++) {
    ans = max(ans, n - p[i] + solve(i));
  }
  cout << ans << endl;
}
int main() {
  ios::sync_with_stdio(false);
  int test = 1;
  cin >> test;
  while (test--) {
    solveTestCase();
  }
  return 0;
}
