#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;

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