#include <bits/stdc++.h>
#include <atcoder/all>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n, m) for (int i = (int)(n); i > (int)(m); i--)
#define rep1(i, n, m) for (int i = (int)(n); i < (int)(m); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend() using namespace atcoder;
using ll = long long;
const ll MOD1 = 1000000007LL;
const ll MOD2 = 998244353LL;
using namespace std;
using namespace atcoder;
const vector<pair<int, int>> dpos4 = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
// const vector<pair<int, int>> dpos8 = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1}, {0, 1}, {1, -1}, {1, 0}, {1, 1}};
template <typename T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;  // aをbで更新
        return true;
    }
    return false;
}
template <typename T>
bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;  // aをbで更新
        return true;
    }
    return false;
}

template<typename T>
T pow(T a, ll b){
    if(b == 0) return 1;
    if(b % 2 == 0) return pow(a / 2, b / 2);
    return a * pow(a, b - 1);
}

int main() {
    int T; cin >> T;
    string base = "helloworld";
    int M = base.size();
    while(T--){
        int N; cin >> N;
        string S; cin >> S;
        string ans = "zzzzzzzzzzzzzzzzzzzzzzzzzzzzz";
        rep(i, N){
            if(i + M - 1 >= N) break;
            bool ok = true;
            string SS = S;
            rep(j, M){
                if(S[i + j] != '?' && S[i + j] != base[j]) ok = false;
                SS[i + j] = base[j];
            }
            SS = regex_replace(SS, regex("\\?"), "a");
            if(ok) chmin(ans, SS);
        }
        if (ans == "zzzzzzzzzzzzzzzzzzzzzzzzzzzzz") ans = "-1";
        cout << ans << '\n';
    }
    return 0;
}