output_description: Print the integer obtained by replacing each occurrence of `1` with `9` and
  each occurrence of `9` with `1` in n.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      n
attempt: import collections
  
  n = input()
  line = input().split()
  odd = line[::2]
  even = line[1::2]
  o = collections.Counter(odd)
  e = collections.Counter(even)
  maxoddcnt = o.most_common()[0][1]
  maxevencnt = e.most_common()[0][1]
  
  # すべての値が同じときは半分を置換する
  if odd == even:
      print(len(odd))
      exit(0)
  
  # 奇数列，偶数列それぞれの最頻の文字が同じ場合は，いずれかを2番目に多い文字に置換しなければならない
  if o.most_common()[0][0] == e.most_common()[0][0]:
      if (
          o.most_common()[1][1] + e.most_common()[0][1]
          > o.most_common()[0][1] + e.most_common()[1][1]
      ):
          maxoddcnt = o.most_common()[1][1]
      else:  # if o.most_common()[1][1] + e.most_common()[0][1] <= o.most_common()[0][1] + e.most_common()[1][1] :
          maxevencnt = e.most_common()[1][1]
  
  print(len(odd) - maxoddcnt + len(even) - maxevencnt)
  
problem_description: Statement
  
  Cat Snuke is learning to write characters. Today, he practiced writing digits
  `1` and `9`, but he did it the other way around.
  
  You are given a three-digit integer n written by Snuke. Print the integer
  obtained by replacing each digit `1` with `9` and each digit `9` with `1` in
  n.
samples: [{"input": "119", "output": "991\n    \n\nReplace the `9` in the ones place with `1`, the `1` in the tens place with `9`\nand the `1` in the hundreds place with `9`. The answer is `991`.\n\n* * *"}, {"input": "999", "output": "111"}]