11050.py

def factorial(n):
  ans = 1
  for i in range(2, n+1):
    ans *= i
  return ans

def bino_coef_factorial(n, r):
  return factorial(n) // factorial(r) // factorial(n-r)

a, b = map(int, input().split())

print(bino_coef_factorial(a, b))