#!/bin/python3

import math
import os
import random
import re
import sys

#
# Complete the 'superDigit' function below.
#
# The function is expected to return an INTEGER.
# The function accepts following parameters:
#  1. STRING n
#  2. INTEGER k
#

def superDigit(n, k):
    # Write your code here
    if len(n) == 1:
        return n
    else:
        digits = [int(x) for x in n] * k
        return superDigit(str(sum(digits)), 1)

if __name__ == '__main__':
    #fptr = open(os.environ['OUTPUT_PATH'], 'w')

    first_multiple_input = input().rstrip().split()

    n = first_multiple_input[0]

    k = int(first_multiple_input[1])

    result = superDigit(n, k)
    print(result)

    #fptr.write(str(result) + '\n')

    #fptr.close()