nCr = {}
def cmb(n, r):
    if r == 0 or r == n: return 1
    if r == 1: return n
    if (n,r) in nCr: return nCr[(n,r)]
    nCr[(n,r)] = cmb(n-1,r) + cmb(n-1,r-1)
    return nCr[(n,r)]


n=int(input())
k=int(input())
l=len(str(n))

def zero(n,k,l):
    saidai=n//(10**(l-1))
    small=n-10**(l-1)*saidai
    if l<k:
        return 0
    elif k==0:
        return 1
    elif l==1:
        return n
    elif l==k:
        return (cmb(l-1,k-1)*9**(k-1)*(saidai-1)+zero(small,k-1,l-1))
    else:
        ans = cmb(l-1,k)*9**k+cmb(l-1,k-1)*9**(k-1)*(saidai-1)+zero(small,k-1,l-1)
        return ans


print(zero(n,k,l))
