#include <bits/stdc++.h>

using namespace std;

void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}

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