#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

string solve(string s) {
    int r = 10;
    int n = s.size();
    string t = "helloworld";
    vector<string> ret;
    for(int i=n-r;i>=0;i--){
        bool ok = true;
        for(int j=0;j<r;j++){
            if(s[i+j]=='?' || s[i+j]==t[j]) continue;
            else ok = false;
        }
        if(ok) {
            string y = s;
            for(int j=0;j<r;j++){
                y[i+j] = t[j];
            }
            rep(j,n) if(y[j]=='?') y[j] = 'a';
            ret.push_back(y);
        }
    }
    if(ret.empty())return "";
    sort(ret.begin(),ret.end());
    return ret.front();
}

int main()
{
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        string s;
        cin >> s;
        auto f = solve(s);
        if(f=="")cout<<-1<<endl;
        else cout<<f<<endl;
    }
    return 0;
}