;; SOLUTION
(defun super-digit (int-str)
  "Parse each char of INT-STR as int then sum and stringify, repeat until single char."
  (if (= (length int-str) 1)
      (parse-integer int-str)
      ;; tail
      (super-digit
       ;; int-str
       (prin1-to-string
        (apply '+
               (mapcar
                (lambda (x) (- (char-int x) 48)) ; 48 is char code of 0
                (coerce int-str 'list)))))))

;; this helps parsing stdin
(defun split-string (str delim)
  (let ((acc '())
        (beg 0))
    (loop while (let ((end (position delim str :start beg)))
                  (progn
                    (push (subseq str beg end) acc)
                    (if end
                        (setq beg (+ 1 end))
                        nil ; break while
                        ))))
    (nreverse acc)))

;; MAIN
(let* ((pair-n-k (split-string (read-line) #\Space))
       (n (car pair-n-k))
       (k (parse-integer (cadr pair-n-k))))
  (write (super-digit (prin1-to-string (* k (super-digit n))))))

def superDigit(n, k):
   # calculate inital n by adding n digits and multiplying it by k
    n = functools.reduce(operator.add,[int(i) for i in str(n)])*k    
    if len(str(n))==1:
       return n 
    return superDigit(int(n),1)

function superDigit(n, k) {
    let sum = n.split('').reduce((a, s) => a + Number(s), 0);
    let next = (sum * k) + "";
    return (next.length == 1) 
        ? Number(next) : superDigit(next, 1);
}

def _super_digit(n):
    if len(str(n)) == 1:
        return n
    return _super_digit(sum([int(c) for c in str(n)]))

def superDigit(n, k):
    initial_super_digit = _super_digit(n)
    return _super_digit(initial_super_digit * k)