def nCkpow(n,k):
    if n<k:
        return 0
    y=1
    for i in range(k):
        y*=n-i
        y//=i+1
        y*=9
    return y
def f(s,m,k):
    #print(m,k)
    if len(s)-m<k:
        return 0
    if  k==0:
        return 1
    if s[m]=='0':
        return f(s,m+1,k)
    l=len(s)-m
    y=nCkpow(l-1,k)
    y+=(int(s[m])-1)*nCkpow(l-1,k-1)
    return y+f(s,m+1,k-1)
N=input()
K=int(input())
print(f(N,0,K))