(print (length
           (filter boolean
                   (map (lambda (day)
                           (let* ((ds (map digit->integer (string->list (number->string day))))
                                  (dsum (apply + ds)))
                               (cond ((> dsum 12) #f)
                                     ((equal? ds '(3 1)) #f)
                                     (else #t))))
                       (iota 31 1)))))