check :: String -> Bool -> String
check str False =if (length str ) == 1 then "No" else
   if(take 1 str)=="C" then check (drop 1 str) True else check (drop 1 str) False
check str True = if(length str) == 0 then "No" else
  if (take 1 str)== "F" then "Yes" else check (drop 1 str) True

main = do
        n <- getLine
        putStrLn (check n False)