from math import factorial as fac

def comb(n,r):
    if ( r<0 or r>n ):
        return 0
    return fac(n)/(fac(r)*fac(n-r))


n=int(input())
k=int(input())

nn=str(n)
keta=len(nn)

ans=0

if keta<k:
    print(0)
    exit()


for i in range(k):
    ans+=comb(keta-i-1,k-i)*9**(k-i)
    if int(nn[i])-1>=0:
        ans+=(int(nn[i])-1)*comb(keta-i-1,k-i-1)*9**(k-i-1)



print(int(ans)+1)