#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

int main() {
    int N;
    string S;
    cin >> N >> S;

    vector<int> ans;
    for (int i = 1; i < N; i++) {
        if (S[i - 1] == 'x' && S[i] == 'o') {
            ans.push_back(i);
        }
    }

    cout << ans.size() << endl;
    for (int x : ans) {
        x++;
        cout << x << ' ';
    }
    cout << endl;
}