#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int T;
int N;
string S;
string Q="helloworld";

bool match(string a) {
	int i;
	FOR(i,10) if(a[i]!='?'&&Q[i]!=a[i]) return 0;
	return 1;
}
string match(string a,int b) {
	int i;
	FOR(i,10) a[b+i]=Q[i];
	FORR(c,a) if(c=='?') c='a';
	return a;
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>T;
	while(T--) {
		cin>>N>>S;
		vector<string> V;
		for(i=0;i+10<=N;i++) {
			if(match(S.substr(i,10))) V.push_back(match(S,i));
		}
		sort(ALL(V));
		if(V.empty()) {
			cout<<-1<<endl;
		}
		else {
			cout<<V[0]<<endl;
		}
	}
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}