#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")

#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
void solve(){
    ll n;cin >> n;string s;cin >> s;
    string ans;rep(i,n)ans+='~';
    string t="helloworld";
    rep(i,n-9){
        string ns=s;
        rep(j,10){
            if(s[i+j]==t[j]||s[i+j]=='?'){
                ns[i+j]=t[j];
            }
            else{
                ns+='~';
            }
        }
        if(ns.size()>n)continue;
        rep(j,n)if(ns[j]=='?')ns[j]='a';
        chmin(ans,ns);
    }
    if(ans[0]=='~')cout << -1 << endl;
    else cout << ans << endl;
}

int main(){
    ll t;cin >> t;
    while(t--){
        solve();
    }
}