#pragma GCC optimize("O3")

#ifdef LOCAL
#include "algo/debug_ver3.hpp"
#else
#define debug(...)
#define debugArr(...)
#endif

#include <bits/stdc++.h>

using namespace std;

int main() {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	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);
		}
	}

	cout << ans.size() << '\n';
	for (int i = 0; i < int(ans.size()); ++i) {
		cout << (i == 0 ? "" : " ") << ans[i] + 1;
	}
	cout << '\n';
}