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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    string s; cin >> s;
    vector<int> answer;
    for(int i=0; i<N-1; i++){
        if(s.at(i) == 'x' && s.at(i+1) == 'o') answer.push_back(i+2);
    }
    
    cout << answer.size() << endl;
    for(int i=0; i<answer.size(); i++) cout << answer.at(i) << " ";
    cout << endl;
}