#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
int main(){
  int i,j,t;
  cin >> t;
  while(t--){
    vector<string> ans;
    int n;
    string s,t="helloworld",s1;
    cin >> n >> s;
    s1=s;
    for(i=n-10;i>=0;i--){
      bool flag=true;
      for(j=i;j<i+10;j++){
        if(!(s[j]==t[j-i] || s[j]=='?')) flag=false;
      }
      if(flag==false) continue;
      for(j=i;j<i+10;j++){
        if(s[j]=='?') s[j]=t[j-i];
      }
      for(j=0;j<i;j++){
        if(s[j]=='?') s[j]='a';
      }
      for(j=i+10;j<n;j++){
        if(s[j]=='?') s[j]='a';
      }
      ans.push_back(s);
      s=s1;
    }
    sort(ans.begin(),ans.end());
    if(ans.size()==0) cout << -1 << endl;
    else cout << ans[0] << endl;
  }
}