output_description: Print the maximum possible number of biscuits in Snuke's pocket after K
  operations.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      K A B
attempt: k,a,b=map(int, input().split())
  
  #aaaabできる。ｃが…
  if a+3<=b and k>=a+1:
    #
    if a%2==0 and k%2==0:
      print(b+1)
    if a%2==0 and not k%2==0:
      print(2b+a)
    if not a%2==0 and k%2==0:
      print(a+1)
    if not a%2==0 and not k%2==0:
      print(2b+a)
problem_description: Statement
  
  Snuke has one biscuit and zero Japanese yen (the currency) in his pocket. He
  will perform the following operations exactly K times in total, in the order
  he likes:
  
    * Hit his pocket, which magically increases the number of biscuits by one.
    * Exchange A biscuits to 1 yen.
    * Exchange 1 yen to B biscuits.
  
  Find the maximum possible number of biscuits in Snuke's pocket after K
  operations.
samples: [{"input": "4 2 6", "output": "7\n    \n\nThe number of biscuits in Snuke's pocket after K operations is maximized as\nfollows:\n\n  * Hit his pocket. Now he has 2 biscuits and 0 yen.\n  * Exchange 2 biscuits to 1 yen. his pocket. Now he has 0 biscuits and 1 yen.\n  * Hit his pocket. Now he has 1 biscuits and 1 yen.\n  * Exchange 1 yen to 6 biscuits. his pocket. Now he has 7 biscuits and 0 yen.\n\n* * *"}, {"input": "7 3 4", "output": "8\n    \n\n* * *"}, {"input": "314159265 35897932 384626433", "output": "48518828981938099"}]