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

int main() {
	int T;
	cin >> T;

	string t = "helloworld";
	int sz = t.size();
	auto fn = [&]( auto it )
	{
		for( int i = 0; i < sz; i++ ) {
			if( *(it + i) != t[i] && *(it + i) != '?' ) return 0;
		}
		return 1;
	};
	for( int i = 0; i < T; i++ ) {
		int N;
		string S;
		cin >> N >> S;
		int f = 0;
		for( int j = N - sz; j >= 0; j-- ) {
			if( j + sz <= N ) {
				if( fn( S.begin() + j ) ) {
					f = 1;
					S.replace( j, sz, t );
					break;
				}
			}
		}
		if( f == 0 ) cout << -1 << endl;
		else {
			for( int i = 0; i < N; i++ ) {
				if( S[i] == '?' ) S[i] = 'a';
			}
			cout << S << endl;
		}
	}
}