-- vim: set fdm=marker : -- {{{
{-# OPTIONS_GHC -O2 #-}
{-# LANGUAGE UnboxedTuples #-}
{-# LANGUAGE BangPatterns #-}
import Control.Monad
import Control.Monad.Fix (fix)
import Data.Maybe
import Data.Array.Unboxed (Array, Ix, array, (!), range)
import qualified Data.ByteString.Char8 as BS

type Index = Int
type Value = Integer
type Data  = Array Index Value

tuplify2 (x:y:_) = (x,y)
tuplify2 _ = undefined

--Input functions with ByteString
readInt :: Num a => BS.ByteString -> a
readInt = fromIntegral . fst . fromJust . BS.readInteger
readIntTuple :: Num a => BS.ByteString -> (a, a)
readIntTuple = tuplify2 . map readInt . BS.words
readIntList :: Num a => BS.ByteString -> [a]
readIntList = map readInt . BS.words

getInt :: Num a => IO a
getInt = readInt <$> BS.getLine
getIntList :: Num a => IO [a]
getIntList = readIntList <$> BS.getLine
getIntNList n = map readIntList <$> replicateM (fromIntegral n) BS.getLine
getIntMatrix = map readIntList . BS.lines <$> BS.getContents
getIntTuple = readIntTuple <$> BS.getLine
getIntNTuples n = map readIntTuple <$> replicateM (fromIntegral n) BS.getLine
getIntTuples = map readIntTuple . BS.lines <$> BS.getContents

genArray n xs = array (0, n-1) [x | x <- zip [0..n] xs]
-- }}}

main = do
    s <- getLine
    putStrLn $ if solve s then "YES" else "NO"

solve :: String -> Bool
solve s = (15 - length s) + win >= 8 where
    win = count (== 'o') s

count :: Ord a => (a -> Bool) -> [a] -> Int
count f = foldl (\acc x -> if f x then acc + 1 else acc) 0
