#ifndef SHO_LOCAL
#include <bits/stdc++.h>
#define debug(...) ;
#else
#include "debug.h"
#endif
#define all(x) (x).begin(), (x).end()
#define lb(x, a) lower_bound(all(x), (a)) - (x).begin()
typedef long long ll;
using namespace std;

static inline vector<int> z_algo(const string &s) {
  int n = (int)s.size();
  vector<int> Z(n);
  int from = -1, until = -1;
  for (int i = 1; i < n; i++) {
    int &a = Z[i];
    if (from != -1) {
      a = max(0, min(Z[i - from], until - i));
    }
    while (i + a < n && (s[i + a] == s[a] || s[i + a] == '?' || s[a] == '?')) {
      a++;
    }
    if (until < i + a) {
      until = i + a;
      from = i;
    }
  }
  Z[0] = n;
  return Z;
}

int main() {
  iostream::sync_with_stdio(0), cin.tie(0);

  int T;
  cin >> T;
  int n;
  string s;
  const string S = "helloworld$";
  while (T--) {
    cin >> n >> s;
    string t = S + s;
    auto Z = z_algo(t);
    bool ok = false;
    for (int i = S.size(); i < (int)Z.size(); i++) {
      if (Z[i] >= 10) {
        ok = true;
        for (int j = 0; j < i; j++) {
          if (t[j] == '?')
            t[j] = 'a';
        }
        for (int j = i; j < i + 10; j++) {
          if (t[j] == '?') {
            t[j] = S[j - i];
          }
        }
        for (int j = i + 1; j < (int)Z.size(); j++) {
          if (t[j] == '?')
            t[j] = 'a';
        }
        cout << t.substr(S.size()) << '\n';
      }
    }
    if (!ok)
      cout << -1 << '\n';
  }

  return 0;
}