#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A& a, const B& b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A& a, const B& b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int t; cin >> t;
	string h = "helloworld";
	while (t--) {
		int n; cin >> n;
		string s; cin >> s;
		vector<int>v;
		rep(i, n - h.size() + 1) {
			bool chk = true;
			rep(j, h.size()) {
				if ('?' == s[i + j])continue;
				if (s[i + j] != h[j])chk = false;
			}
			if (chk)v.push_back(i);
		}
		if (v.empty()) {
			cout << -1 << endl;
			continue;
		}
		vector<string>vs;
		rep(i, v.size()) {
			string ss = s;
			int idx = v[i];
			rep(j, h.size())ss[j + idx] = h[j];
			rep(j, s.size())if ('?' == ss[j])ss[j] = 'a';
			vs.push_back(ss);
		}
		sort(all(vs));
		cout << vs[0] << endl;
	}
	return 0;
}