(defun format-print-cardinal-aux (stream n period err)
(multiple-value-bind (beyond here) (truncate n 1000)
- (unless (<= period 20)
+ (unless (<= period 21)
(error "number too large to print in English: ~:D" err))
(unless (zerop beyond)
(format-print-cardinal-aux stream beyond (1+ period) err))