#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>;
using vl = vector<long long>;

#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() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n;

	cin >> n;

	vector <char> S(n);

	rep(i, 0, n){
		cin >> S[i];
	}

	if(n == 1){
		cout << "0\n\n";
		return 0;
	}

	int count = 0;
	vi result;
	bool sp;

	if(S[0] == 'x') sp = true;
	else sp = false;

	rep(i, 1, n){
		if(S[i] == 'o' && sp){ //tava dormindo ai acordo
			count++;
			result.pb(i+1);
			sp = false;
		}

		if(S[i] == 'x' && !sp){ //tava acordado ai dormiu
			sp = true;
		}
	}

	cout << count << "\n";

	for(auto a : result){
		cout << a << " ";
	}

	cout << "\n";

	return 0;
}