#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

void solve() {
  int N;
  string S, T, C = "helloworld";
  cin >> N >> S;
  int pos = -1, j = 0;
  for (int i = 0; i < S.size(); i++) {
    if (S[i] == C[j] || S[i] == '?') {
      if (j == 0) pos = i;
      j++;
      if (j == 10) break;
    } else {
      j = 0;
      pos = -1;
    }
  }
  if (pos != -1 && j < 10) pos = -1;
  if (pos == -1) {
    cout << -1 << endl;
    return;
  }
  for (int i = 0; i < S.size(); i++) {
    if (i == pos) {
      T += C;
      i += 9;
    } else if (S[i] == '?') {
      T += 'a';
    } else {
      T += S[i];
    }
  }
  cout << T << endl;
}

int main() {
  int T; cin >> T;
  while (T--) solve();
  return 0;
}