import sys
input = sys.stdin.readline
N, K = map(int, input().split())
D = [[0 for j in range(N+1)] for i in range(N+1)]

for i in range(0, N+1):
    D[i][1] = i
    D[i][0] = 1
    D[i][i] = 1

for i in range(2, N+1):
    for j in range(1, i):
        D[i][j] = D[i-1][j] + D[i-1][j-1]

print(D[N][K])

import sys
input = sys.stdin.readline
N, K = map(int, input().split())
D = [[0 for j in range(N+1)] for i in range(N+1)]

for i in range(0, N+1):
    D[i][1] = i
    D[i][0] = 1
    D[i][i] = 1

for i in range(2, N+1):
    for j in range(1, i):
        D[i][j] = D[i-1][j] + D[i-1][j-1]
        D[i][j] = D[i][j] % 10007

print(D[N][K])

import sys
input = sys.stdin.readline
D = [[0 for j in range(15)] for i in range(15)]

for i in range(1, 15):
    D[i][1] = 1
    D[0][i] = i

for i in range(1, 15):
    for j in range(2, 15):
        D[i][j] = D[i][j-1] + D[i-1][j]

T = int(input())

for i in range(0, T):
    K = int(input())
    N = int(input())
    print(D[K][N])

import sys
input = sys.stdin.readline
D = [[0 for j in range(31)] for i in range(31)]

for i in range(0, 31):
    D[i][1] = i
    D[i][0] = 1
    D[i][i] = 1

for i in range(2, 31):
    for j in range(1, i):
        D[i][j] = D[i-1][j] + D[i-1][j-1]

t = int(input())

for i in range(0, t):
    N, M = map(int, input().split())
    print(D[M][N])

D = [0] * 51
probability = [0] * 51
M = int(input())
D = list(map(int, input().split()))
T = 0

for i in range(0, M):
    T += D[i]
    
K = int(input())
ans = 0

for i in range(0, M):
    if D[i] >= K:
        probability[i] = 1
        for k in range(0, K):
            probability[i] = probability[i] * (D[i] - k) / (T-k)
        ans += probability[i]

print(ans)