#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int N;
  cin >> N;
  string S;
  cin >> S;
  vector<int> ans;
  rep(i, N-1) {
    int k = i+1;
    if (S[k-1] == 'x' && S[k] == 'o')
      ans.push_back(k+1);
  }
  cout << ans.size() << endl;
  rep(i, ans.size())
    cout << ans[i] << " ";
  cout << endl;
  return 0;
}