#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using VS = vector<string>;
using P = pair<ll,ll>;
using VP = vector<P>;
#define rep(i, n) for (ll i = 0; i < ll(n); i++)
#define out(x) cout << x << endl
#define dout(x) cout << fixed << setprecision(10) << x << endl
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define sz(x) (int)(x.size())
#define re0 return 0
#define pcnt __builtin_popcountll
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
constexpr int inf = 1e9;
constexpr ll INF = 1e18;
//using mint = modint1000000007;
using mint = modint998244353;
int di[4] = {1,0,-1,0};
int dj[4] = {0,1,0,-1};

void solve(){
    int n;
    string s;
    cin >> n >> s;
    string t = "helloworld";
    auto judge = [&](string ns){
        rep(i,sz(t)){
            if(t[i] == ns[i]) continue;
            if(ns[i] == '?') continue;
            return false;
        }
        return true;
    };
    string ans;
    rep(i,n-sz(t)+1){
        string ns = s.substr(i,sz(t));
        if(judge(ns)){
            string tmp = s;
            for(int j = 0;j < n;j++){
                if(i <= j && j < i+sz(t)){
                    tmp[j] = t[j-i];
                }
                if(tmp[j] == '?') tmp[j] = 'a';
            }
            if(ans == "") ans = tmp;
            else chmin(ans,tmp);
        }
    }
    if(ans != "") out(ans);
    else out(-1);
}

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