/* -*- coding: utf-8 -*-
 *
 * 2226.cc:  No.2226 Hello, Forgotten World! - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 1000;
const int L = 10;
const char T[] = "helloworld";

/* typedef */

/* global variables */

char s[MAX_N + 4];

/* subroutines */

bool match(char w[]) {
  for (int i = 0; i < L; i++)
    if (w[i] != '?' && w[i] != T[i]) return false;
  return true;
}

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int n;
    scanf("%d%s", &n, s);

    int k = n - L;
    for (; k >= 0; k--)
      if (match(s + k)) break;
    if (k < 0) { puts("-1"); continue; }

    for (int i = 0; i < L; i++) s[k + i] = T[i];
    for (int i = 0; i < n; i++)
      if (s[i] == '?') s[i] = 'a';

    puts(s);
  }
  return 0;
}