import Control.Monad
import Control.Applicative
import Data.List


main :: IO()
main = do
  [a, b, c] <- map read . words <$> getLine
  print $ solve [a, b, c]


solve :: [Int] -> Int
solve [a, b, c] = (f a [b, c]) + (f b [a, c]) + (f c [a, b])
    where
      f :: Int -> [Int] -> Int
      f c lst = if c `elem` lst then 0 else c
