#include <iostream>
#include <string>
using namespace std;

void solve(){
    int N;
    cin >> N;
    string S;
    cin >> S;

    bool pos = false;
    string ans;
    for (int i = 0; i < N; i++) ans += 'z';

    string hw = "helloworld";
    for (int i = 0; i < N - 9; i++){
        string Sb = S.substr(i, 10);
        bool can = true;
        for (int j = 0; j < 10; j++){
            if (Sb[j] != hw[j] && Sb[j] != '?'){
                can = false;
            }
        }
        if (!can) continue;
        pos = true;
        string T;
        for (int j = 0; j < N; j++){
            if (S[j] == '?'){
                if (j >= i && j < i + 10){
                    T += hw[j - i];
                }
                else{
                    T += 'a';
                }
            }
            else{
                T += S[j];
            }
        }
        if (T < ans){
            ans = T;
        }
    }
    if (pos) cout << ans << endl;
    else cout << -1 << endl;
    return;
}

int main(){
    int T;
    cin >> T;
    while(T--){
        solve();
    }
    return 0; 
}