#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using ll=long long;
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

const string h="helloworld";

void solve(){
    int n;
    string s;
    cin>>n>>s;
    int l=h.size();
    vector<string>V;
    rep(i,n-l+1){
        bool flag=true;
        rep(j,l){
            if(s[i+j]=='?'||s[i+j]==h[j])continue;
            flag=false;
            break;
        }
        if(flag){
            string t=s;
            rep(j,l)t[i+j]=h[j];
            rep(j,n)if(t[j]=='?')t[j]='a';
            V.push_back(t);
        }
    }
    if(V.empty()){
        cout<<-1<<"\n";
        return;
    }
    sort(all(V));
    cout<<V[0]<<"\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin>>t;
    while(t--){
        solve();
    }
}