T = gets.to_i

target = 'helloworld'

T.times do
  n = gets.to_i
  s = gets.chomp
  best_idx = -1

  (n - 10).downto(0) do |i|
    ok = true
    idx = 0

    while ok && idx < 10
      if target[idx] == s[i + idx] || s[i + idx] == '?'
        # NOOP
      else
        ok = false
      end

      idx += 1
    end

    if ok
      best_idx = i
      break
    end
  end

  if best_idx != -1
    10.times do |i|
      if s[best_idx + i] == '?'
        s[best_idx + i] = target[i]
      end
    end

    s.tr!('?', 'a')
    puts s
  else
    puts -1
  end
end