#include <bits/stdc++.h>
#define rep(i, p, n) for (ll i = p; i < (ll)(n); i++)
#define rep2(i, p, n) for (ll i = p; i >= (ll)(n); i--)
using namespace std;
using ll = long long;
using ld = long double;
const double pi = 3.141592653589793;
const long long inf = 2 * 1e9;
const long long linf = 4 * 1e18;
const ll mod1 = 1000000007;
const ll mod2 = 998244353;
template <class T>
inline bool chmax(T &a, T b)
{
    if (a < b)
    {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return 1;
    }
    return 0;
}

// atcoder
#include <atcoder/all>
using namespace atcoder;
using mint1 = modint1000000007;
using mint2 = modint998244353;

vector<pair<ll, ll>> base = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

int main()
{

    //////////////////
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    //////////////////

    ll T;
    cin >> T;
    string F = "helloworld";
    while(T--) {
        ll N;
        string S;
        cin >> N >> S;
        bool done = false;
        rep(i, 0, N-9) {
            bool ch = true;
            rep(j, 0, 10) {
                if (S.at(i+j)!=F.at(j)) {
                    ch = false;
                }
            }
            if (ch) {
                done = true;
                rep(j, 0, N) {
                    if (S.at(i)=='?') {
                        S.at(i) = 'a';
                    }
                }
                break;
            }
        }
        rep2(i, N-10, 0)
        {
            if (done) {
                break;
            }
            bool ch = true;
            rep(j, 0, 10) {
                if (S.at(i+j)!=F.at(j) && S.at(i+j)!='?') {
                    ch = false;
                }
            }
            if (ch) {
                done = true;
                rep(j, 0, 10) {
                    S.at(i + j) = F.at(j);
                }
                break;
            }
        }
        if (!done) {
            cout << -1 << endl;
        }
        else {
            rep(i, 0, N) {
                if (S.at(i)=='?') {
                    cout << 'a';
                }
                else {
                    cout << S.at(i);
                }
            }
            cout << endl;
        }
    }
}