import Control.Monad
import qualified Data.ByteString.Char8 as BS
import Data.Maybe (fromJust)
import Data.List as List

getRemainCount :: Int -> Int
getRemainCount 0 = 0
getRemainCount x
    | x <= 6 = 1
    | otherwise = 2

solve :: Int -> Int
solve s = a
    where
        c = (div s 11) * 2
        m = mod s 11
        a = c + getRemainCount m    


main :: IO()
main = do
    s <- read <$> getLine :: IO Int
    print $ solve s
