#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(){
  int t;cin>>t;
  string x = "helloworld";
  for(int i = 0; t > i; i++){
    int n;cin>>n;
    string s;cin>>s;
    bool exi = false;
    vector<string> X;
    for(int j = s.size()-10; 0 <= j; j--){
      bool ok = true;
      for(int k = 0; 10 > k; k++){
        if(!(s[j+k] == x[k] || s[j+k] == '?')){
          ok = false;
          break;
        }
      }
      if(ok){
        string ret = "";
        for(int k = 0; s.size() > k; k++){
          if(j <= k && k < j+10){
            ret.push_back(x[k-j]);
          }else{
            ret.push_back(s[k]=='?'?'a':s[k]);
          }
        }
        X.push_back(ret);
        exi = true;
      }
    }
    if(!exi)cout << "-1" << endl;
    else{
      sort(X.begin(), X.end());
      cout << X[0] << endl;
    }
  }
}