#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define codefor int test;cin>>test;while(test--)
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define vector2d(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define vector3d(type,name,h,w,...) vector<vector<vector<type>>>name(h,vector<vector<type>>(w,vector<type>(__VA_ARGS__)))
using namespace std;
using ll = long long;
template<class T> using rpriority_queue = priority_queue<T, vector<T>, greater<T>>;
template<class T> istream& operator>>(istream& is, vector<T>& vec) {for(T& x : vec)is >> x;return is;}
template<class T> ostream& operator<<(ostream& os, const vector<T>& vec) {if(vec.empty())return os;os << vec[0];for(auto it = vec.begin(); ++it!= vec.end();)os << ' ' << *it;return os;}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){cin >> head;in(tail...);}
void out(){cout << '\n';}
template<class T>void out(const T& a){cout << a << '\n';}
template <class Head, class... Tail> void out(const Head& head,const Tail&... tail){cout << head << ' ';out(tail...);}
const int INF = 1 << 30;
const long long INF2 = 1ll << 60;
template<class T> void chmax(T &a,const T b){if(b>a)a=b;}
template<class T> void chmin(T &a,const T b){if(b<a)a=b;}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    string t = "helloworld";
    reverse(all(t));
    int T;
    cin >> T;
    while(T--){
        INT(n);
        string s;
        cin >> s;
        reverse(all(s));
        if(n < t.size()){
            out(-1);
            continue;
        }
        bool f = false;
        for(int i = 0; i < s.size(); i++){
            if(f){
                if(s[i] == '?')s[i] = 'a';
                continue;
            }
            bool f2 = true;
            for(int j = 0; j < t.size(); j++){
                if(i + j >= s.size()){
                    f2 = false;
                    break;
                }
                if(s[i + j] == '?') continue;
                if(t[j] != s[i + j]){
                    f2 = false;
                    break;
                }
            }
            if(f2){
                f = true;
                for(int j = 0; j < t.size() && i + j < s.size(); j++){
                    s[i + j] = t[j];
                }
            }else{
                if(s[i] == '?') s[i] = 'a';
            }
        }
        if(!f){
            out(-1);
            continue;
        }
        reverse(all(s));
        out(s);
    }
}