#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(int)n;i++)

int main(){
	int n;
	cin >> n;
	string S;
	cin >> S;
	vector<int> a;
	int count=0;
	for(int i=1;i<n;i++){
		if(S.at(i)=='o' and S.at(i-1)=='x'){
			count++;
			a.push_back(i+1);
		}	
	}
	cout << count << endl;
	sort(a.begin(),a.end());
	rep(i,a.size()){
		if(i+1==a.size())cout << a[i] << endl;
		else cout << a[i] << " ";
	}
}