문제의 조건 때문에 가운데 경우에 해당됨
import math
from sys import stdin
n, k= map(int, stdin.readline().split())
def fac(a):
result = 1
for i in range(1, a+1, 1):
result *= i
return result
a = fac(n)
b = fac(k)
c = fac(n-k)
print(a // (b * c))
import math
from sys import stdin
n, k= map(int, stdin.readline().split())
def fac(n):
if n > 1:
return n * fac(n-1)
else:
return 1
a = fac(n)
b = fac(k)
c = fac(n-k)
print(a // (b * c))
import math
from sys import stdin
n, k= map(int, stdin.readline().split())
a = math.factorial(n)
b = math.factorial(k)
c = math.factorial(n-k)
print(a // (b * c))