#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int cmp_char_arr (const void *a, const void *b) {
  return strcmp((char *)a, (char *)b);
}

int main () {
  int t = 0;
  int n = 0;
  char s[1011] = "";
    
  int res = 0;
  
  char ans[1000][1001] = {};
  char hw[11] = "helloworld";
  
  res = scanf("%d", &t);
  while (t > 0) {
    res = scanf("%d", &n);
    res = scanf("%s", s);
    for (int i = 0; i < n; i++) {
      int is_ok = 1;
      for (int j = 0; j < 10; j++) {
        if (s[i+j] != '?' && s[i+j] != hw[j]) {
          is_ok = 0;
        }
      }
      if (is_ok > 0) {
        for (int j = 0; j < n; j++) {
          if (s[j] == '?') {
            ans[i][j] = 'a';
          } else {
            ans[i][j] = s[j];
          }
        }
        for (int j = 0; j < 10; j++) {
          ans[i][i+j] = hw[j];
        }
      } else {
        for (int j = 0; j < n; j++) {
          ans[i][j] = '~';
        }
      }
      ans[i][n] = '\0';
    }
    qsort(ans, n, sizeof(char)*1001, cmp_char_arr);
    if (ans[0][0] == '~') {
      printf("-1\n");
    } else {
      printf("%s\n", ans[0]);
    }
    t--;
  }
  
  return 0;
}