using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var s = ReadLine();
        var ans = new List<int>();
        for (var i = 1; i < s.Length; ++i) if (s[i - 1] == 'x' && s[i] == 'o') ans.Add(i + 1);
        WriteLine(ans.Count);
        WriteLine(string.Join(" ", ans));
    }
}