output_description: Print `Yes` if the string `CF` can be obtained from the string s by deleting
  some characters. Otherwise print `No`.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      s
attempt: def main()
      s = input()
      f = False
      if s.count('C') == 0 or s.count('F') == 0:
          print('NO')
          return
      for i in range(len(s)):
          if s[i] == 'C':
              for j in range(i, len(s)):
                  if s[j] == 'F':
                      print('Yes')
                      f = True
                      break
              if f == False:
                  print('No')
  main()
problem_description: Statement
  
  This contest is `CODEFESTIVAL`, which can be shortened to the string `CF` by
  deleting some characters.
  
  Mr. Takahashi, full of curiosity, wondered if he could obtain `CF` from other
  strings in the same way.
  
  You are given a string s consisting of uppercase English letters. Determine
  whether the string `CF` can be obtained from the string s by deleting some
  characters.
samples: [{"input": "CODEFESTIVAL", "output": "Yes\n    \n\n`CF` is obtained by deleting characters other than the first character `C` and\nthe fifth character `F`.\n\n* * *"}, {"input": "FESTIVALCODE", "output": "No\n    \n\n`FC` can be obtained but `CF` cannot be obtained because you cannot change the\norder of the characters.\n\n* * *"}, {"input": "CF", "output": "Yes\n    \n\nIt is also possible not to delete any characters.\n\n* * *"}, {"input": "FCF", "output": "Yes\n    \n\n`CF` is obtained by deleting the first character."}]