#include <bits/stdc++.h>
using namespace std;
const string key = "helloworld";
bool OK(string& s, int j) {
    for (int i = 0; i < 10; i ++) {
        if (s[i + j] != key[i] && s[i + j] != '?') {
            return false;
        }
    }
    for (int i = 0; i < 10; i ++) {
        s[i + j] = key[i];
    }
    return true;
}
void solve() {
    int N;
    string s;
    cin >> N >> s;
    if (N < 10) {
        cout << -1 << endl;
        return;
    }
    string ret = "{-1";
    for (int i = 0; i <= N - 10; i ++) {
        if (s.substr(i, 10) == key) {
            ret = s;
            for (auto& c : ret) {
                c = (c == '?' ? 'a' : c);
            }
            break;
        }
    }
    string ss = s;
    for (int i = N - 10; i >= 0; i --) {
        ss = s;
        if (OK(ss, i)) {
            for (auto& c : ss) {
                c = (c == '?' ? 'a' : c);
            }
            ret = min(ret, ss);
        }
    }
    if (ret[0] == '{') {
        cout << -1 << endl;
    } else {
        cout << ret << endl;
    }
    return;
}
int main () {
    int N;
    cin >> N;
    for (int i = 0; i < N; i ++) {
        solve();
    }
}