#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)s; i < (int)e; i++)

string key = "helloworld";

int main() {
    cin.tie(nullptr);
    
    int T;
    cin >> T;
    
    rep(testcase, 0, T) {
        int N;
        string S;
        cin >> N >> S;
        
        int t = -1;
        rep(s, 0, N - 10 + 1) {
            bool res = true;
            
            rep(i, 0, 10) {
                if (S[s + i] != '?' && S[s + i] != key[i]) res = false;
            }
            
            if (res) t = s;
        }
        
        if (t == -1) {
            cout << -1 << '\n';
            continue;
        }
        
        rep(i, 0, 10) {
            S[t + i] = key[i];
        }
        
        rep(i, 0, N) {
            if (S[i] == '?') cout << 'a';
            else cout << S[i];
        }
        
        cout << '\n';
    }
}