#include<bits/stdc++.h>
using namespace std;
int main(){
	int s; cin >> s;
	string str; cin >> str;
	vector<int> ans;
	for(int i = 2; i < str.length(); i++){
		if(str[i] != str[i - 1] && str[i] == 'o' && str[i - 1] == 'x'){
			ans.push_back(i + 1);
		}
	}
	cout << ans.size() << endl;
	for(int i = 0; i < ans.size(); i++){
		cout << ans[i] << " ";
	}
	return 0;
}