import math
from operator import mul
from functools import reduce

def cmb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(mul, range(n, n - r, -1))
    under = reduce(mul, range(1,r + 1))
    return over // under

answer=0

n=int(input())
k=int(input())
#keta=math.floor(math.log(n, 10))
now=n
keta=0
while now!=0:
    now=now//10
    keta+=1
keta-=1

moto=10**keta
first=n//moto
if k>=2:
    second=(n-first*moto)//(moto//10)
    if k>=3:
        third=(n-first*moto-second*(moto//10))//(moto//100)
#print(keta)
#print(first, second)
if keta>=k:
    answer+=cmb(keta, k)*(9**k)
answer+=max(first-1, 0)*cmb(keta, k-1)*(9**(k-1))
#print(answer)
if k==1:
    answer+=1
elif k==2:
    if keta>=k:
        answer+=cmb(keta-1, k-1)*(9**(k-1))
    answer+=cmb(keta-1, k-2)*max(second-1, 0)*(9**(k-2))
    if keta>=k:
        answer+=cmb(keta-2, k-2)*(9**(k-2))
    else:
        answer+=1
else:
    if keta>=k:
        answer+=cmb(keta-1, k-1)*(9**(k-1))
    answer+=cmb(keta-1, k-2)*max(second-1, 0)*(9**(k-2))
    if keta>=k:
        answer+=cmb(keta-2, k-2)*(9**(k-2))
    if keta>=k:
        answer+=third
    else:
        answer+=1

print(answer)