#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>;

#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()
{
    cin.tie(0)->sync_with_stdio(0);

   int n;
   cin >> n;
   string s;
   cin >> s;
   vector<int> ans;
   rep(i,1,n){
        if(s[i] == 'x') continue;
        if(s[i] == 'o' && s[i-1] == 'x') ans.pb(i+1);
   }

   cout << sz(ans) << endl;
   rep(i,0,sz(ans)){
        if(i) cout << " ";
        cout << ans[i];
   }

    return 0;
}