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

using ll = long long;

int main()
{
	int T;
	cin >> T;
	int N; string S;
	const string B = "helloworld";
	bool pos;
	for(int test = 0; test < T; test++)
	{
		cin >> N >> S;
		pos = false;
		for(int i = N - 10; i >= 0; i--)
		{
			for(int j = 0; j < 10; j++)
			{
				if(S[i + j] != B[j] && S[i + j] != '?') break;
				if(j == 9) pos = true;
			}
			
			if(pos)
			{
				for(int j = 0; j < 10; j++) S[i + j] = B[j];
				for(int j = 0; j < N; j++) if(S[j] == '?') S[j] = 'a';
				cout << S << endl;
				break;
			}
		}
		if(!pos) cout << -1 << endl;
	}
	return 0;
}