output_description: Print the length of the longest even string that can be obtained.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
attempt: S = input()
  result = ''
  for i in range(1, len(S)):
      s = S[0:len(S) - i]
  	if len(s) % 2 == 0 and s[0:len(s)//2] == s[len(s)//2:]:
          result = len(s)
          break
  
  print(result)
  
problem_description: Statement
  
  We will call a string that can be obtained by concatenating two equal strings
  an _even_ string. For example, `xyzxyz` and `aaaaaa` are even, while `ababab`
  and `xyzxy` are not.
  
  You are given an even string S consisting of lowercase English letters. Find
  the length of the longest even string that can be obtained by deleting one or
  more characters from the end of S. It is guaranteed that such a non-empty
  string exists for a given input.
samples: [{"input": "abaababaab", "output": "6\n    \n\n  * `abaababaab` itself is even, but we need to delete at least one character.\n  * `abaababaa` is not even.\n  * `abaababa` is not even.\n  * `abaabab` is not even.\n  * `abaaba` is even. Thus, we should print its length, 6.\n\n* * *"}, {"input": "xxxx", "output": "2\n    \n\n  * `xxx` is not even.\n  * `xx` is even.\n\n* * *"}, {"input": "abcabcabcabc", "output": "6\n    \n\nThe longest even string that can be obtained is `abcabc`, whose length is 6.\n\n* * *"}, {"input": "akasakaakasakasakaakas", "output": "14\n    \n\nThe longest even string that can be obtained is `akasakaakasaka`, whose length\nis 14."}]