#include<bits/stdc++.h>
using namespace std;

#define INF 1234567890
#define ll long long

int T;
int N;
string s;
string H = "helloworld";

int main()
{
	ios::sync_with_stdio(0); cin.tie(0);
	cin.exceptions(ios::badbit | ios::failbit);
	cin >> T;
	while(T--)
	{
		cin >> N >> s;
		string res = string(1, '~');
		for(int i=0; i+9<N; i++)
		{
			string t = s;

			int die = 0;
			for(int j=0; j<10; j++)
			{
				if (t[i+j] == '?')
					t[i+j] = H[j];
				else if (t[i+j] != H[j])
					die = 1;
			}
			if (die) continue;

			for(char &c : t)
				if (c == '?')
					c = 'a';

			res = min(res, t);
		}
		if (res == "~") res = "-1";
		cout << res << "\n";
	}
	return 0;
}