#include <bits/stdc++.h>

using namespace std;

string x = "helloworld";

void solve() {
    int n;
    string s;
    cin >> n >> s;
    vector<string> can;
    for (int i = n - (int) x.size(); i >= 0; i--) {
        string t = s;
        bool ok = true;
        for (int j = 0; j < (int) x.size(); j++) {
            if (t[i + j] != '?' && t[i + j] != x[j]) {
                ok = false;
                break;
            } else {
                t[i + j] = x[j];
            }
        }
        if (ok) {
            for (auto&& c : t) {
                if (c == '?') {
                    c = 'a';
                }
            }
            can.push_back(t); 
        }
    }
    if (can.size()) {
        sort(can.begin(), can.end());
        cout << can[0] << endl;
        return;
    } else {
        cout << -1 << endl;
        return;
    }
}

int main() {
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
}