import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		char[] s = sc.next().toCharArray();
		sc.close();

		int cnt = 0;
		StringBuilder sb = new StringBuilder();
		for (int i = 1; i < n; i++) {
			if (s[i - 1] == 'x' && s[i] == 'o') {
				cnt++;
				sb.append(i + 1).append(' ');
			}
		}
		System.out.println(cnt);
		if (cnt > 0) {
			sb.deleteCharAt(sb.length() - 1);
		}
		System.out.println(sb.toString());
	}
}