from math import log10

try:

  while True:

    k, n = input().split()

    k, n = int(k), int(n)

    a, b, c = 0, 0, 0

    for i in range(1, k + 1):

      a = a + log10(i)

    for i in range(1, n + 1):

      b = b + log10(i)

    for i in range(1, k - n + 1):

      c = c + log10(i)

    ans = a - b - c

    print(int(ans) + 1)

except EOFError:

  pass