#include<bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  string S;
  cin >> S;
  vector<int> A;
  for (int i = 1; i <= N; i++) {
    if (S[i - 1] == 'x' && S[i] == 'o') {
      A.push_back(i + 1);
    }
  }
  int M = A.size();
  cout << M << endl;
  for (int i = 0; i < M; i++) {
    cout << A[i] << ' ';
  }
  cout << endl;
}