output_description: Print the area of this yard excluding the roads (in square yards).
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B
attempt: import math
  
  N = int(input())
  
  
  # def yakusuu(x):
  #     tmplist=list(sy.factorint(x).values())
  #     a=1
  #     for i in tmplist:
  #         a*=i+1
  #     return a
  def make_prime_list_2(num):
      if num < 2:
          return []
  
      # 0のものは素数じゃないとする
      prime_list = [i for i in range(num + 1)]
      prime_list[1] = 0  # 1は素数ではない
      num_sqrt = math.sqrt(num)
  
      for prime in prime_list:
          if prime == 0:
              continue
          if prime > num_sqrt:
              break
  
          for non_prime in range(2 * prime, num, prime):
              prime_list[non_prime] = 0
  
      return [prime for prime in prime_list if prime != 0]
  
  
  def search_divisor_num_1(num):
      if num < 0:
          return None
      elif num == 1:
          return 1
      else:
          num_sqrt = math.floor(math.sqrt(num))
          prime_list = make_prime_list_2(num_sqrt)
  
          divisor_num = 1
          for prime in prime_list:
              count = 1
              while num % prime == 0:
                  num //= prime
                  count += 1
              divisor_num *= count
  
          if num != 1:
              divisor_num *= 2
  
          return divisor_num
  
  
  counter = 0
  for i in range(1, N + 1, 2):
      if search_divisor_num_1(i) == 8:
          counter += 1
  print(counter)
  
problem_description: Statement
  
  There is a farm whose length and width are A yard and B yard, respectively. A
  farmer, John, made a vertical road and a horizontal road inside the farm from
  one border to another, as shown below: (The gray part represents the roads.)
  
  ![ ](https://img.atcoder.jp/ghi/27d063746b460f1132b6a99aa535a562.png)
  
  What is the area of this yard excluding the roads? Find it.
samples: [{"input": "2 2", "output": "1\n    \n\nIn this case, the area is 1 square yard.\n\n* * *"}, {"input": "5 7", "output": "24\n    \n\nIn this case, the area is 24 square yards."}]