#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <cstring>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i,n) for (int i = 0; i < int(n);i++)
const ll mod = 998244353;

void slove(){
  int n;
  cin >> n;
  string s;
  cin >> s;
  string ans = "{}";
  string h = "helloworld";
  for (int i = n-10; i >= 0;i--){
    string t = s;
    bool can = true;
    for (int j = i; j < i+10;j++){
      if (t[j] == h[j-i]) continue;
      else if (t[j] == '?'){
        t[j] = h[j-i];
        continue;
      } 
      else{
        //cout << "i:" << i << " j:" << j << endl;
        can = false;
        break;
      }
    }
    if (can){
      for (int j = 0; j < n;j++){
        if (t[j] == '?') t[j] = 'a'; 
      }
      //cout << "i:" << i << endl;
      //cout << t << endl;
      ans = min(ans,t);
    }
  }
  if (ans == "{}"){
    cout << -1 << endl;
  }
  else{
    cout << ans << endl;
  }
}
int main(){
  int t;
  cin >> t;
  while(t--){
    slove();
  }
  
  return 0;
}