#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vll = vector<long long>;
using vvll = vector<vector<long long>>;
using vs = vector<string>;
using vb = vector<bool>;
using vvb = vector<vector<bool>>;
#define lln \
  ll n;     \
  cin >> n;
#define REP(i, n) for (long long i = 0; i < n; i++)
#define REPIN(v, n) \
  for (long long i = 0; i < n; i++) cin >> v[i];
ll gcd(ll x, ll y) { return (x % y) ? gcd(y, x % y) : y; }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }

int main() {
  ll T;
  cin >> T;
  string hello = "helloworld";
  REP(t, T) {
    ll n, cnt;
    string s;
    bool J, K;
    cin >> n >> s;
    cnt = -1;
    REP(i, n) {
      if (s[i] == hello[0] || s[i] == '?') {
        J = true;
        K = true;
        REP(j, hello.size()) {
          if (!(i + j < n)) {
            J = false;
            break;
          }
          if (s[i + j] == hello[j] || s[i + j] == '?') {
            if (s[i + j] == hello[j]) {
              K = true;
            } else {
              K = false;
            }
          } else {
            J = false;
            break;
          }
        }
        if (J) {
          cnt = i;
          if (K) {
            break;
          }
        }
      }
    }
    if (cnt == -1) {
      cout << -1 << endl;
    } else {
      REP(i, n) {
        if (cnt <= i && i < cnt + hello.size()) {
          cout << hello[i - cnt];
        } else {
          cout << ((s[i] == '?') ? 'a' : s[i]);
        }
      }
      cout << endl;
    }
  }
  return 0;
}