N = int(input())
K = int(input())

M = 6 * N # 出しうる最大の値

edited = [4,4,5,5,6,6]
normal = [1,2,3,4,5,6]

def f(X):
  x = [0] * (M + 1)
  x[0] = 1
  dice = normal
  for i in range(N):
    new_x = [0] * (M + 1)
    for j in range(M + 1):
      if x[j] == 0:
        continue
      if i >= (N - K): # normalを(N - K)回以上使っていたら、Xに切り替える
        dice = X
#      print("dice",dice,"を振る")
      for k in range(6):
#        print(j + dice[k],"に",x[j] / 6,"の確率で到達")
        new_x[j + dice[k]] += x[j] / 6
#        print("new_x",new_x)
    x = new_x
  return x
  
jiro = f(normal)
taro = f(edited)

ans = 0
jiro_lose = 0
for i in range(len(taro)):
  ans += taro[i] * jiro_lose
  jiro_lose += jiro[i]
  
print(ans)