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

using ll = long long;
#define rep(i, n) for(int i = 0; i < n; i++)

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