from scipy.special import comb
#base = comb(5, 3, exact=True)
n=int(input())
k=int(input())

l=n
l=str(l)
keta=len(l)
num=[0 for i in range(keta)]
ans=0
m=n
for i in range(keta):
  num[i]=m%10
  m//=10
#print(num)
if k==1:
  ans+=num[-1]+(keta-1)*9
if k==2:
  ans+=(num[-1]-1)*(keta-1)*9
  for i in range(keta-1):
    if i!=keta-2:
      ans+=9
    else:
      ans+=num[i]
  if keta>=3:
    ans+=comb(keta-1,2,exact=True)*81
if k==3:
  ans+=comb(keta-1,3,exact=True)*729
  ans+=(num[-1]-1)*comb(keta-1,2,exact=True)*81
  ans+=(num[-2]-1)*(keta-2)*9
  for i in range(keta-2):
    ans+=num[i]
print(ans)
