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: i = 105
  N = input()
  N = int(N)
  m = 5
  n = 0
  x = 0
  y = 0
  while i <= N:
      if i % 2 != 0:
          if i % 3 == 0:
              n = int(i / 3)
              while m < n:
                  if i % m == 0:
                      x = x + 1
                  m = m + 2
              if x == 4:
                  y = y + 1
      x = 0
      n = 0
      m = 5
      i = i + 1
  print(y)
  
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."}]