n = input()
k = int(input())
m = len(n)
if k == 1:
    print(int(n[0])+9*(m-1))
elif k == 2:
    if m<2:ans = 0
    else:
        ans = 81*(m-1)*(m-2)//2
        ans += (int(n[0])-1)*(m-1)*9+int(n[1])+(m-2)*9
    print(ans)
else:
    if m<3:ans = 0
    else:
        ans1 = (m-1)*(m-2)*(m-3)//6*9**3
        ans2=(int(n[0])-1)*(m-1)*(m-2)//2*81
        ans3 =(m-2)*(m-3)//2*81
        ans = ans1+ans2+ans3
        if int(n[1]) > 0:
            ans += (int(n[1])-1)*(m-2)*9 + (m-3)*9+int(n[2])
    print(ans)