#include <bits/stdc++.h>
//#include<atcoder/all>
using namespace std;
//using namespace atcoder;
#define all(x) (x).begin(), (x).end()
#define rep1(a)          for(int i = 0; i < a; i++)
#define rep2(i, a)       for(int i = 0; i < a; i++)
#define rep3(i, a, b)    for(int i = a; i < b; i++)
#define rep4(i, a, b, c) for(int i = a; i < b; i += c)
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep(i, a, b) for (int i = a; i >= b; i--)
#define fore(i, a) for (auto &i : a)
#define rfore(a) for(auto i=a.rbegin(), e=a.rend(); i!=e; ++i)
#define enld endl
#define fix(n) cout << fixed << setprecision(n);
#define debug(var)  do{std::cout << #var << " : ";view(var);}while(0)
template<typename T> void view(T e){std::cout << e << std::endl;}
template<typename T> void view(const std::vector<T>& v){for(const auto& e : v){ std::cout << e << " "; } std::cout << std::endl;}
template<typename T> void view(const std::vector<std::vector<T> >& vv){ for(const auto& v : vv){ view(v); } }
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
template<class T>using rp_queue=priority_queue<T,vector<T>,greater<T>>;
void fast_io(){cin.tie(nullptr);ios_base::sync_with_stdio(false);}
typedef long long ll;
typedef unsigned long long ull;
const int inf = INT_MAX / 2;
const ll infl = 1LL<<60;
const ll mod = 1000000007;
const int dx[8] = {0, 1, 0,-1, 1, 1,-1,-1};
const int dy[8] = {1, 0,-1, 0, 1,-1, 1,-1};

int main() {
    fast_io();
    int T; cin >> T;
    string seek = "helloworld";
    while(T--) {
        int n; cin >> n;
        string s; cin >> s;
        rep(10) s += '.';
        set<string>st;
        rep(i,n) {
            bool jud = 1;
            rep(j,10) if(s[i+j]!='?' && s[i+j]!=seek[j]) jud = 0;
            if(!jud) continue;
            string t = s;
            rep(j,10) t[i+j] = seek[j];
            st.insert(t);
        }

        if(st.size()==0) cout << -1 << enld;
        else {
            string ans = *begin(st);
            rep(i,ans.size()-10) cout << (ans[i]=='?' ? 'a':ans[i]);
            cout << endl;
        }
    }
}