Problem:
Score : 200 points

Problem Statement

Takahashi is competing in a sumo tournament.
The tournament lasts for 15 days, during which he performs in one match per day.
If he wins 8 or more matches, he can also participate in the next tournament.

The matches for the first k days have finished.
You are given the results of Takahashi's matches as a string S consisting of o and x.
If the i-th character in S is o, it means that Takahashi won the match on the i-th day; if that character is x, it means that Takahashi lost the match on the i-th day.

Print YES if there is a possibility that Takahashi can participate in the next tournament, and print NO if there is no such possibility.

Constraints

1 \leq k \leq 15

S is a string of length k consisting of o and x.

Input

Input is given from Standard Input in the following format:

S

Output

Print YES if there is a possibility that Takahashi can participate in the next tournament, and print NO otherwise.

Sample Input 1

oxoxoxoxoxoxox

Sample Output 1

YES

Takahashi has 7 wins and 7 losses before the last match. If he wins that match, he will have 8 wins.

Sample Input 2

xxxxxxxx

Sample Output 2

NO

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

{-# LANGUAGE BangPatterns      #-} --引数に!

import Data.Bits
import Data.Foldable (foldlM,foldrM)
import Data.Maybe (fromJust)
import Data.List
import qualified Data.Vector.Unboxed.Mutable as V
import Control.Monad
import qualified Data.ByteString.Lazy.Char8 as BS
import Debug.Trace

cnt :: [Char] -> Int
cnt [] = 0
cnt (a:s) = if a == 'o' then 1 + (cnt s) else cnt s

main :: IO ()
main = do
  s <- getLine
  if (cnt s)+(15 - (length s)) >= 8 then putStrLn $ "YES" else putStrLn "NO"