#include <vector>
#include <iostream>
#include <string>
#include <ostream>
#include <map>
#include <set>
#include <bitset>
#include <cmath>
#include <iomanip>
#include <algorithm>
#include <list>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;

int main()
{
    int n;
    string s;
    cin >> n >> s;
    vector<int> a;
    bool bl = false;
    rep(i, n - 1) if (s[i] == 'x' && s[i + 1] == 'o')
    {
        a.push_back(i + 1);
        bl = true;
    }
    sort(a.begin(), a.end());
    cout << a.size() << endl;
    if (bl)
    {
        rep(i, a.size())
        {
            if (i == a.size() - 1)
                cout << a[i] + 1;
            else
                cout << a[i] + 1 << " ";
        }
    }
    else
        cout << 0;
}