main :: IO ()
main = interact $ show . solve . map read . words

solve :: [Int] -> Int
solve (x:y:r:_) = ceiling (z + w)
    where
        z :: Float
        z = fromIntegral (abs x + abs y)
        w :: Float
        w = sqrt 2 * (fromIntegral r) -- * 2 * 1 / 2