for _ in range(int(input())):
  n = int(input())
  s = list(map(str, input()))
  t = list(map(str, "helloworld"))
  ng = 1
  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 ng:
    print(-1)
    continue
  for i in reversed(range(n)):
    if s[i] == "?":
      s[i] = "a"
  print(*s, sep = "")