#include<bits/stdc++.h>
using namespace std;
using ll=long long;

int main(){
  ll n;
  cin>>n;
  string s;
  cin>>s;
  vector<ll> ans;
  if(s[0]=='o'){
    ans.push_back(1);
  }
  for(ll i=1;i<n;i++){
    if(s[i-1]=='x'&&s[i]=='o'){
      ans.push_back(i+1);
    }
  }
  cout<<ans.size()<<endl;
  for(ll a:ans){
    cout<<a<<" ";
  }
}