#include <bits/stdc++.h>
using namespace std;
 
#define fi first
#define se second
#define pb push_back
using vi = vector <int>;
using ll = long long;
using vl = vector <ll>;
using pii = pair <int, int>;
const ll mod = 998244353;
//~ const ll mod = 1e9 + 7;
ll qpow(ll a, ll b, ll m = mod) { ll r = 1, t = a;
	for(; b; b /= 2) { if(b & 1) r = r * t % m; t = t * t % m; } return r; }



int main() {
	ios::sync_with_stdio(0);
	int T; cin >> T;
	while(T --) {
		int n; cin >> n;
		string s; cin >> s;
		
		string ans = "";
		string t = "helloworld";
		
		bool can = 0;
		
		for(int i = n - t.size(); i >= 0; i --) {
			bool f = 1;
			for(int j = 0; j < t.size(); j ++)
				if(s[i + j] != '?' && s[i + j] != t[j])
					f = 0;
			
			if(f) {
				string r = s;
				for(int j = 0; j < t.size(); j ++)
					r[i + j] = t[j];
				for(auto &c : r)
					if(c == '?') c = 'a';
				
				if(!can)
					ans = r;
				else if(r < ans)
					ans = r;
					
				can = 1;
			}
		}
		
		if(!can) ans = "-1";
		cout << ans << '\n';
		
	}
}