#include<bits/stdc++.h>
using namespace std;
#include<atcoder/all>
using namespace atcoder;
using ll = long long;
string s;
string HW = "helloworld";
bool is(string t){
	for(int i = 0;i<t.size();i++){
		if(t[i]=='?'){
		}else if(HW[i]==t[i]){
		}else{
			return false;
		}
	}
	return true;
}

void solve(){
	int sz = s.size();
	for(int i = s.size()-HW.size();i>=0;i--){
		string t = s.substr(i,HW.size());
		if(is(t)){
			for(int j = i;j<i+HW.size();j++){
				s[j]=HW[j-i];
			}
			for(auto &j:s){
				if(j=='?'){
					j = 'a';
				}
			}
			cout<<s<<endl;
			return;
		}
	}
	cout<<-1<<endl;
}

signed main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	int t;
	cin >> t;
	while(t--){
		int sz;
		cin >> sz;
		cin >> s;
		solve();
	}
}