백준 11050.이항계수 1 브론즈1

from sys import stdin
N, K = map(int,input().split()) # n r
def binary(x):
    if x == 0:
        return 1
    else:
        return x * binary(x-1)
# starttime = time.time()
print(binary(N) // (binary(K) * binary(N-K)))
# print(time.time()- starttime)