// 

#include <bits/stdc++.h>
using namespace std;

using ll = long long;

#define rep(i, n) for (int i=0; i<(int)(n); ++(i))
#define rep3(i, m, n) for (int i=(m); (i)<(int)(n); ++(i))
#define repr(i, n) for (int i=(int)(n)-1; (i)>=0; --(i))
#define rep3r(i, m, n) for (int i=(int)(n)-1; (i)>=(int)(m); --(i))
#define all(x) (x).begin(), (x).end()

const string tar = "helloworld";

int main() {
    int t0;
    cin >> t0;
    rep(i0, t0) {
        int n;
        string s;
        cin >> n >> s;
        bool exist = false;
        int tlen = tar.length();
        for (int i=0; i+tlen-1<n; ++i) if (s.substr(i, tlen) == tar) {
            exist = true;
            break;
        }
        if (!exist) {
            for (int i=n-tlen; i>=0; --i) {
                bool ok = true;
                rep(j, tlen) if (s[i+j]!='?' && s[i+j]!=tar[j]) {
                    ok = false;
                    break;
                }
                if (ok) {
                    rep(j, tlen) s[i+j] = tar[j];
                    exist = true;
                    break;
                }
            }
        }
        if (exist) {
            rep(i, n) if (s[i] == '?') s[i] = 'a';
            cout << s << endl;
        }
        else cout << -1 << endl;
        
    }
    return 0;
}