import sys
n = int(input())
k = int(input())
keta = len(str(n))
from math import factorial
if k <= keta:
    al = (factorial(keta) / factorial(k) / factorial(keta - k)) * 81
    diff = 0
    if k == 2:
        diff += (9-int(str(n)[0]))*9*(keta-1)
        diff += 9-int(str(n)[1])
    elif k == 3:
        c = (factorial(keta-1) / factorial(k) / factorial(keta-1 - k))
        diff += (9-int(str(n)[0]))*81*c
        c = (factorial(keta-2) / factorial(k) / factorial(keta-2 - k))
        diff += (9-int(str(n)[1]))*9*c
        diff += 9-int(str(n)[2])
    elif k == 1:
        diff += 9-int(str(n)[0])
    al = (factorial(keta) / factorial(k) / factorial(keta - k)) * (9**k)
    print(int(al-diff))
else:
    print(0)