#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <set>
#include <random>
#include <iomanip>
#include <string>
#include <cmath>
#include <complex>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)

template<class T>
using vi = vector<T>;

template<class T>
using vii = vector<vi<T>>;

template<class T>
using viii = vector<vii<T>>;

template<class T>
using viiii = vector<viii<T>>;

using P = pair<ll, int>;

void chmin(ll & x, ll y) { x = min(x, y); }

void chmax(ll& x, ll y) { x = max(x, y); }

int main()
{
    int n;
    string s;
    cin >> n >> s;

    vi<int> ans;
    rep(i, n - 1) {
        if (s[i] == 'x' && s[i + 1] == 'o') ans.push_back(i + 2);
    }
    int sz = (int)ans.size();
    cout << sz << endl;
    rep(i, sz) cout << ans[i] << " \n"[i == sz - 1];
    if (sz == 0) cout << endl;
    return 0;
}