#include <bits/stdc++.h>
using namespace std;
#include<cassert>
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vvvvll = vector<vvvll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using vvvvb = vector<vvvb>;
using vd = vector<double>;
using vvd = vector<vd>;
using vvvd = vector<vvd>;
#define all(A) A.begin(),A.end()
#define ALL(A) A.begin(),A.end()
#define rep(i, n) for (ll i = 0; i < (ll) (n); i++)
using pqr = priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>;

template<class T>
bool chmax(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p < q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

template<class T>
bool chmin(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p > q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

ll gcd(ll(a), ll(b)) {
    if (b == 0)return a;
    if (a == 0)return b;
    ll c = a;
    while (a % b != 0) {
        c = a % b;
        a = b;
        b = c;
    }
    return b;
}


ll mod = 998244353;
ll modPow(long long a, long long n, long long p) {
    a %= p;
    if (n == 0) return 1; // 0乗にも対応する場合
    if (n == 1) return a % p;
    if (n % 2 == 1) return (a * modPow(a, n - 1, p)) % p;
    long long t = modPow(a, n / 2, p);
    return (t * t) % p;
}


ll inv(ll N) {
    return modPow(N, mod - 2, mod);
}


int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll T;
    cin>>T;
    string K="helloworld";
    rep(t,T){
        ll N;
        string S;
        cin>>N>>S;
        ll d=-1;
        vector<string> AN;
        rep(i,N-9){
            bool OK=1;
            string P=S.substr(i,10);
            rep(k,10)if(P[k]!='?'&&P[k]!=K[k])OK=0;
            if(OK){
                d=i;
                string res="";
                rep(j,N){
                    if(S[j]!='?')res.push_back(S[j]);
                    else if(j<d||j-9>d)res.push_back('a');
                    else res.push_back(K[j-d]);
                }
                AN.push_back(res);
            }
        }
        
        if(d<0)cout<<-1<<endl;
        else{
            sort(all(AN));
            cout<<AN[0]<<endl;
            
        }
    }

}