#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001


int main(){
	
	int n;
	cin>>n;
	string s;
	cin>>s;
	vector<int> ans;
	rep(i,n){
		if(i==0)continue;
		if(s[i-1]=='x'&&s[i]=='o'){
			ans.push_back(i+1);
		}
	}
	cout<<ans.size()<<endl;
	rep(i,ans.size()){
		if(i!=0)cout<<' ';
		cout<<ans[i];
	}
	cout<<endl;
	return 0;
}