#include <iostream>
#include <string>
using namespace std;
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)

const string target = "helloworld";
string solve(string S) {
    const int N = S.size();

    string candidate;
    candidate += (char)('z' + 1);

    IREP(i, N - int(target.size()) + 1) {
        bool good = true;
        REP(j, target.size()) {
            if (S.at(i + j) == '?') continue;
            if (S.at(i + j) != target.at(j)) good = false;
        }
        if (good) {
            string T = S;
            REP(j, target.size()) T.at(i + j) = target.at(j);
            for (auto &c : T)
                if (c == '?') c = 'a';
            candidate = min(candidate, T);
        }
    }
    if (candidate.size() <= 1) return "-1";
    return candidate;
}

int main() {
    cin.tie(nullptr), ios::sync_with_stdio(false);
    int T;
    cin >> T;
    while (T--) {
        int N;
        string S;
        cin >> N >> S;
        cout << solve(S) << '\n';
    }
}