// #pragma GCC target("avx")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i = 0; i < (int)n; i++)
#define FOR(n) for(int i = 0; i < (int)n; i++)
#define repi(i,a,b) for(int i = (int)a; i < (int)b; i++)
#define all(x) x.begin(),x.end()
//#define mp make_pair
#define vi vector<int>
#define vvi vector<vi>
#define vvvi vector<vvi>
#define vvvvi vector<vvvi>
#define pii pair<int,int>
#define vpii vector<pair<int,int>>

template<typename T>
void chmax(T &a, const T &b) {a = (a > b? a : b);}
template<typename T>
void chmin(T &a, const T &b) {a = (a < b? a : b);}

using ll = long long;
using ld = long double;
using ull = unsigned long long;

const ll INF = numeric_limits<long long>::max() / 2;
const ld pi = 3.1415926535897932384626433832795028;
const ll mod = 998244353;
int dx[] = {1, 0, -1, 0, -1, -1, 1, 1};
int dy[] = {0, 1, 0, -1, -1, 1, -1, 1};

#define int long long

const string t = "helloworld";

void solve() {
    int n;
    string s;
    cin >> n >> s;

    int id = -1;

    rep(i, n) {
        bool flag = true;
        rep(j, t.size()) {
            if(i+j >= n) {
                flag = false;
                break;
            }
            if(s[i+j] == t[j] || s[i+j] == '?') {}
            else {
                flag = false;
                break;
            }
        }

        if(flag) {
            id = i;
        }
    }

    if(id == -1) {
        cout << -1 << endl;
    }else {
        rep(i, n) {
            if(i == id) {
                rep(j, t.size()) s[i+j] = t[j];
                i += t.size()-1;
            }else if(s[i] == '?') {
                s[i] = 'a';
            }
        }

        cout << s << endl;
    }
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int t;
    cin >> t;
    while(t--) solve();
    return 0;
}