#include <bits/stdc++.h>
using namespace std;
void fft(vector<complex<double> > &a, bool inv) {
  int n = a.size(), j = 0;
  vector<complex<double> > roots(n / 2);
  for (int i = 1; i < n; i++) {
    int bit = (n >> 1);
    while (j >= bit) {
      j -= bit;
      bit >>= 1;
    }
    j += bit;
    if (i < j) swap(a[i], a[j]);
  }
  double ang = 2 * acos(-1) / n * (inv ? -1 : 1);
  for (int i = 0; i < n / 2; i++) {
    roots[i] = complex<double>(cos(ang * i), sin(ang * i));
  }
  for (int i = 2; i <= n; i <<= 1) {
    int step = n / i;
    for (int j = 0; j < n; j += i) {
      for (int k = 0; k < i / 2; k++) {
        complex<double> u = a[j + k], v = a[j + k + i / 2] * roots[step * k];
        a[j + k] = u + v;
        a[j + k + i / 2] = u - v;
      }
    }
  }
  if (inv)
    for (int i = 0; i < n; i++) a[i] /= n;
}
vector<int> multiply(vector<int> &v, vector<int> &w) {
  vector<complex<double> > fv(v.begin(), v.end()), fw(w.begin(), w.end());
  int n = 2;
  while (n < v.size() + w.size()) n <<= 1;
  fv.resize(n);
  fw.resize(n);
  fft(fv, 0);
  fft(fw, 0);
  for (int i = 0; i < n; i++) fv[i] *= fw[i];
  fft(fv, 1);
  n = v.size() + w.size() - 1;
  vector<int> ret(n);
  for (int i = 0; i < n; i++) ret[i] = (int)round(fv[i].real());
  return ret;
}
string s;
vector<int> A, B, C, D, E, F1, F2;
vector<int> res, u[500005];
int dd[500005];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(NULL);
  for (int i = 1; i <= 500000; i++) {
    for (int j = 1; j <= 500000 / i; j++) {
      u[i * j].push_back(i);
    }
  }
  int t;
  cin >> t;
  for (int z = 1; z <= t; z++) {
    int n;
    cin >> n;
    cin >> s;
    A = vector<int>(n);
    B = vector<int>(n);
    for (int i = 0; i <= n - 1; i++) {
      if (s[i] == 'V') {
        A[i] = 1;
      } else if (s[i] == 'K') {
        B[n - 1 - i] = 1;
      }
    }
    C = multiply(A, B);
    for (int i = 0; i <= 2 * n - 2; i++) {
      if (C[i]) {
        int k = abs(n - 1 - i);
        if (dd[k]) continue;
        for (auto j : u[k]) {
          dd[j] = 1;
        }
      }
    }
    for (int i = 1; i <= n; i++) {
      if (!dd[i]) res.push_back(i);
      dd[i] = 0;
    }
    printf("%d\n", res.size());
    for (int i = 0; i < res.size(); i++) printf("%d ", res[i]);
    printf("\n");
    res.clear();
  }
  return 0;
}
