#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
struct Sync_stdio {
  Sync_stdio() {
    cin.tie(NULL);
    ios_base::sync_with_stdio(false);
  }
} _sync_stdio;
struct FAIL {
  FAIL() {
    cout << "CHANGE!!!"
         << "\n";
  }
};
using Base = std::complex<double>;
vector<vector<int>> rev;
void fft(vector<Base> &a, int log_n, bool invert) {
  int nn = 1 << log_n;
  for (int i = 0; i < nn; ++i) {
    if (i < rev[log_n][i]) {
      std::swap(a[i], a[rev[log_n][i]]);
    }
  }
  vector<Base> wlen_pw(nn);
  for (int len = 2; len <= nn; len <<= 1) {
    double ang = 2 * 3.14159265358979323846264338327 / len * (invert ? -1 : +1);
    int len_two = len >> 1;
    Base wlen(cos(ang), sin(ang));
    wlen_pw[0] = Base(1, 0);
    for (int i = 1; i < len_two; ++i) {
      wlen_pw[i] = wlen_pw[i - 1] * wlen;
    }
    for (int i = 0; i < nn; i += len) {
      Base t;
      int pu = i;
      int pv = i + len_two;
      int pu_end = i + len_two;
      int pw = 0;
      for (; pu != pu_end; ++pu, ++pv, ++pw) {
        t = a[pv] * wlen_pw[pw];
        a[pv] = a[pu] - t;
        a[pu] += t;
      }
    }
  }
  if (invert) {
    for (int i = 0; i < nn; ++i) {
      a[i] /= nn;
    }
  }
}
void calc_rev(int len_n, int log_n) {
  rev[log_n].resize(len_n);
  for (int i = 0; i < len_n; ++i) {
    rev[log_n][i] = 0;
    for (int j = 0; j < log_n; ++j) {
      if (i & (1 << j)) {
        rev[log_n][i] |= 1 << (log_n - 1 - j);
      }
    }
  }
}
void init_rev() {
  const int LOG = 21;
  int MAXN = 1 << LOG;
  rev.resize(MAXN);
  for (int i = 0; i < LOG; ++i) {
    calc_rev(1 << i, i);
  }
}
vector<long long> multiply(const vector<int> &first,
                           const vector<int> &second) {
  int n = max(first.size(), second.size());
  vector<Base> a(n);
  vector<Base> b(n);
  for (int i = 0; i < first.size(); ++i) {
    a[i] = first[i];
  }
  for (int i = 0; i < second.size(); ++i) {
    b[i] = second[i];
  }
  int len_k = 2 * n;
  while (len_k & (len_k - 1)) {
    ++len_k;
  }
  while (a.size() < len_k) {
    a.push_back(0);
  }
  while (b.size() < len_k) {
    b.push_back(0);
  }
  int log_k = 31 - __builtin_clz(len_k);
  fft(a, log_k, 0);
  fft(b, log_k, 0);
  for (int i = 0; i < len_k; ++i) {
    a[i] *= b[i];
  }
  fft(a, log_k, 1);
  vector<long long> res(len_k);
  for (int i = 0; i < len_k; ++i) {
    res[i] = a[i].real() + 0.5;
  }
  return res;
}
void solve() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  vector<int> a(n);
  vector<int> b(n);
  for (int i = (0); i < (n); ++i) {
    if (s[i] == 'V') {
      a[i] = 1;
    } else if (s[i] == 'K') {
      b[i] = 1;
    }
  }
  reverse(b.begin(), b.end());
  vector<long long> res = multiply(a, b);
  reverse(a.begin(), a.end());
  reverse(b.begin(), b.end());
  vector<long long> res2 = multiply(a, b);
  for (int i = (0); i < (res2.size()); ++i) {
    res[i] = !!res[i] | !!res2[i];
  }
  res.resize(n - 1);
  res.insert(res.begin(), 0);
  reverse(res.begin(), res.end());
  for (int i = (1); i < (n + 1); ++i) {
    for (int j = i; j < n + 1; j += i) {
      res[i - 1] |= res[j - 1];
    }
  }
  vector<int> ans;
  for (int i = (1); i < (n + 1); ++i) {
    if (res[i - 1] == 0) {
      ans.push_back(i);
    }
  }
  cout << ans.size() << "\n";
  for (auto elem : ans) {
    cout << elem << " ";
  }
  cout << "\n";
}
int main() {
  init_rev();
  int n;
  cin >> n;
  for (int i = (0); i < (n); ++i) {
    solve();
  }
}
