output_description: Print `Yes` if S follows the postal code format in AtCoder Kingdom; print `No`
  otherwise.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B
      S
attempt: a,b = map(int,input().split())
  s = input()
  L = [i for i in range(1,10)]
  ans = "Yes"
  for i in range(a):
    if  not int(s[i]) in L:
      ans = "No"
  if s[a] != "-":
    ans = "No"
  for i in range(a+1,a+b+1):
      if  not int(s[i]) in L:
      ans = "No"
  print(ans)
problem_description: Statement
  
  The postal code in Atcoder Kingdom is A+B+1 characters long, its (A+1)-th
  character is a hyphen `-`, and the other characters are digits from `0`
  through `9`.
  
  You are given a string S. Determine whether it follows the postal code format
  in Atcoder Kingdom.
samples: [{"input": "3 4\n    269-6650", "output": "Yes\n    \n\nThe (A+1)-th character of S is `-`, and the other characters are digits from\n`0` through `9`, so it follows the format.\n\n* * *"}, {"input": "1 1\n    ---", "output": "No\n    \n\nS contains unnecessary `-`s other than the (A+1)-th character, so it does not\nfollow the format.\n\n* * *"}, {"input": "1 2\n    7444", "output": "No"}]