output_description: If there is a price that satisfies the condition, print an integer
  representing the lowest such price; otherwise, print `-1`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B
attempt: # N = int(input())
  A, B = map(int, input().split())
  # X=list(map(int,input().split()))
  
  a = int(A / 0.08)
  b = int(B / 0.1)
  aa = []
  bb = []
  if int(a * 0.08) == A:
      aa.append(a)
  if int(b * 0.1) == B:
      bb.append(b)
  au = a + 1
  ap = a - 1
  bu = b + 1
  bs = b - 1
  f1 = True
  f2 = True
  f3 = True
  f4 = True
  
  while f1 == True or f2 == True:
      if int(au * 8 / 100) == A:
          aa.append(au)
          au += 1
      else:
          f1 = False
  
      if int(ap * 8 / 100) == A:
          aa.append(ap)
          ap -= 1
      else:
          f2 = False
  
  while f3 == True or f4 == True:
      if int(bu * 10 / 100) == B:
          bb.append(bu)
          bu += 1
      else:
          f3 = False
  
      if int(bs * 8 / 100) == B:
          bb.append(bs)
          bs -= 1
      else:
          f4 = False
  cc = []
  for i in aa:
      for j in bb:
          if i == j:
              cc.append(j)
  if len(cc) == 0:
      print(-1)
  else:
      print(min(cc))
  
problem_description: Statement
  
  Find the price of a product before tax such that, when the consumption tax
  rate is 8 percent and 10 percent, the amount of consumption tax levied on it
  is A yen and B yen, respectively. (Yen is the currency of Japan.)
  
  Here, the price before tax must be a positive integer, and the amount of
  consumption tax is rounded down to the nearest integer.
  
  If multiple prices satisfy the condition, print the lowest such price; if no
  price satisfies the condition, print `-1`.
samples: [{"input": "2 2", "output": "25\n    \n\nIf the price of a product before tax is 25 yen, the amount of consumption tax\nlevied on it is:\n\n  * When the consumption tax rate is 8 percent: \\lfloor 25 \\times 0.08 \\rfloor = \\lfloor 2 \\rfloor = 2 yen.\n  * When the consumption tax rate is 10 percent: \\lfloor 25 \\times 0.1 \\rfloor = \\lfloor 2.5 \\rfloor = 2 yen.\n\nThus, the price of 25 yen satisfies the condition. There are other possible\nprices, such as 26 yen, but print the minimum such price, 25.\n\n* * *"}, {"input": "8 10", "output": "100\n    \n\nIf the price of a product before tax is 100 yen, the amount of consumption tax\nlevied on it is:\n\n  * When the consumption tax rate is 8 percent: \\lfloor 100 \\times 0.08 \\rfloor = 8 yen.\n  * When the consumption tax rate is 10 percent: \\lfloor 100 \\times 0.1 \\rfloor = 10 yen.\n\n* * *"}, {"input": "19 99", "output": "-1\n    \n\nThere is no price before tax satisfying this condition, so print `-1`."}]