for _ in range(int(input())):
  n = int(input())
  s = list(map(str, input()))
  t = list(map(str, "helloworld"))
  if not "".join(t) in "".join(s):
    for i in reversed(range(n-9)):
      flg = 1
      for j in range(10):
        if s[i+j] != t[j] and s[i+j] != "?":
          flg = 0
          break
      if flg:
        s = s[:i] + t + s[i+j+1:]
        ng = 0
        break
    if not "".join(t) in "".join(s):
      print(-1)
      continue
  for i in reversed(range(n)):
    if s[i] == "?":
      s[i] = "a"
  print(*s, sep = "")