#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

const string hello_world = "helloworld";

void solve() {
  int n; string s; cin >> n >> s;
  if (s.find(hello_world) != s.npos) {
    cout << regex_replace(s, regex(R"(\?)"), "a") << '\n';
    return;
  }
  for (int i = n - hello_world.length(); i >= 0; --i) {
    bool matches = true;
    REP(j, hello_world.length()) {
      matches &= s[i + j] == '?' || s[i + j] == hello_world[j];
    }
    if (matches) {
      s.replace(i, hello_world.length(), hello_world);
      cout << regex_replace(s, regex(R"(\?)"), "a") << '\n';
      return;
    }
  }
  cout << "-1\n";
}

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