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

int main()
{
    int N;
    string S;
    cin >> N >> S;
    vector<int> ans;
    for (int i = 0; i < N - 1; i++)
    {
        if (S[i] == 'x' && S[i + 1] == 'o')
        {
            ans.push_back(i + 2);
        }
    }
    cout << ans.size() << "\n";
    for (auto s : ans)
    {
        cout << s << " ";
    }
}