#include <bits/stdc++.h> 
#include <atcoder/all>
#define pub push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i, n) rep2(i, 0, n)
#define rep2(i, m, n) for (ll i = m; i < (n); i++)
#define per(i, b) per2(i, 0, b)
#define per2(i, a, b) for (ll i = int(b) - 1; i >= int(a); i--)
#define ALL(c) (c).begin(), (c).end()
using namespace std;
using namespace atcoder;
using ll = long long; using dd = double;
using Pll = pair<ll, ll>;
using    vll = vector<   ll>; using  vdd = vector< dd>;
using   vvll = vector<  vll>; using vvdd = vector<vdd>;
using  vvvll = vector< vvll>; using vvvdd = vector<vvdd>;
using vvvvll = vector<vvvll>;
using mint = modint998244353;
using mint2 = modint1000000007;

constexpr long long INF = (1LL << 60);
constexpr double EPS = 1e-9;
constexpr double PI = 3.141592653589;

//////////////////////////////////////////////////////////

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 sq(T x) {
	return x * x;
}

std::string zfill(int n, const int width)
{
	std::stringstream ss;
	ss << std::setw(width) << std::setfill('0') << n;
	return ss.str();
}


string he = "helloworld";

int main() {
	//cout << fixed << setprecision(10);
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	ll t; cin >> t;
	rep(x, t) {
		ll N; cin >> N;
		string S; cin >> S;
		set<ll> last;
		rep(i, N - 9) {
			bool ok = true;
			
			rep(j, 10) {
				if (S[i + j] == he[j] || S[i + j] == '?') {
					continue;
				}
				else {
					ok = false;
					break;
				}
			}
			if (ok) {
				last.insert(i);
			}
		}
		if (last.empty()) {
			cout << -1 << endl;
		}
		else {
			string ans;
			for (auto a : last) {
				string T = S;
				for (int i = 0; i <= 9; i++) {
					T[a + i] = he[i];
				}
				rep(i, N) {
					if (T[i] == '?') {
						T[i] = 'a';
					}
				}
				if (ans.empty()) {
					ans = T;
				}
				chmin(ans, T);
			}
			
			cout << ans << endl;
		}
	}
}