#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;

#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define rep(i,a,b) for (int i = (a); i < (b); i++)

mt19937 rng(random_device{}());

int main() {
	cin.tie(0)->sync_with_stdio(0);
	int n;
	string s;
	cin >> n >> s;
	vector<int> ans;
	for (int i = 1; i < n; i++) {
		if (s[i] == 'o' && s[i - 1] == 'x') {
			ans.push_back(i + 1);
		}
	}
	cout << ans.size() << endl;
	for (auto i: ans) cout << i  << ' ';;
}