#include <bits/stdc++.h>

//#include <atcoder/all>
using namespace std;

#define lli long long int
#define REP(i, s, n) for (lli i = s; i < n; i++)
#define INF (1LL << 62)
#define mp(a, b) make_pair(a, b)
#define SORT(V) sort(V.begin(), V.end())
#define PI (3.141592653589794)
#define TO_STRING(VariableName) #VariableName
#define LOG1(x)                                                                \
  if (DEBUG)                                                                   \
    cout << TO_STRING(x) << "=" << x << " " << endl;
#define LOG2(x, y)                                                             \
  if (DEBUG)                                                                   \
    cout << TO_STRING(x) << "=" << x << " " << TO_STRING(y) << "=" << y << endl;
#define LOG3(x, y, z)                                                          \
  if (DEBUG)                                                                   \
    cout << TO_STRING(x) << "=" << x << " " << TO_STRING(y) << "=" << y << " " \
         << TO_STRING(z) << "=" << z << endl;
#define LOG4(w, x, y, z)                                                       \
  if (DEBUG)                                                                   \
    cout << TO_STRING(w) << "=" << w << " " << TO_STRING(x) << "=" << x << " " \
         << TO_STRING(y) << "=" << y << " " << TO_STRING(z) << "=" << z        \
         << endl;
#define LOG5(w, x, y, z, a)                                                    \
  if (DEBUG)                                                                   \
    cout << TO_STRING(w) << "=" << w << " " << TO_STRING(x) << "=" << x << " " \
         << TO_STRING(y) << "=" << y << " " << TO_STRING(z) << "=" << z << " " \
         << TO_STRING(a) << "=" << a << endl;
#define LOG6(w, x, y, z, a, b)                                                 \
  if (DEBUG)                                                                   \
    cout << TO_STRING(w) << "=" << w << " " << TO_STRING(x) << "=" << x << " " \
         << TO_STRING(y) << "=" << y << " " << TO_STRING(z) << "=" << z << " " \
         << TO_STRING(a) << "=" << a << " " << TO_STRING(b) << "=" << b        \
         << endl;

#define overload6(a, b, c, d, e, f, g, ...) g
#define LOG(...)                                                               \
  overload6(__VA_ARGS__, LOG6, LOG5, LOG4, LOG3, LOG2, LOG1)(__VA_ARGS__)

template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

mt19937 engine;
std::chrono::system_clock::time_point start, endTime;

#define DEBUG 0

void solve() {
  //  write your code here

  lli N;
  string s;
  cin >> N >> s;

  string t = "x" + s;

  vector<lli> v;
  lli ans = 0;
  REP(i, 0, t.size() - 1) {
    if (t[i] == 'x' && t[i + 1] == 'o') {
      ans++;
      v.push_back(i);
    }
  }
  cout << ans << endl;
  for (auto e : v) {
    cout << e + 1 << " ";
  }
  cout << endl;
}

// Generated by 2.13.0 https://github.com/kyuridenamida/atcoder-tools  (tips:
// You use the default template now. You can remove this line by using your
// custom template)
int main() {
  // Failed to predict input format

  lli N = 1;
  // cin >> N;
  while (N--)
    solve();

  return 0;
}