Problem:
Score : 300 points

Problem Statement

You are given three integers A, B and C. Find the minimum number of operations required to make A, B and C all equal by repeatedly performing the following two kinds of operations in any order:

Choose two among A, B and C, then increase both by 1.

Choose one among A, B and C, then increase it by 2.

It can be proved that we can always make A, B and C all equal by repeatedly performing these operations.

Constraints

0 \leq A,B,C \leq 50

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the minimum number of operations required to make A, B and C all equal.

Sample Input 1

2 5 4

Sample Output 1

2

We can make A, B and C all equal by the following operations:

Increase A and C by 1. Now, A, B, C are 3, 5, 5, respectively.

Increase A by 2. Now, A, B, C are 5, 5, 5, respectively.

Sample Input 2

2 6 3

Sample Output 2

5

Sample Input 3

31 41 5

Sample Output 3

23

Solution in Haskell (GHC 8.8.3) (judge verdict: Accepted)

import qualified Data.ByteString.Char8 as BS
import Data.Maybe

readInt = fst . fromJust . BS.readInt
readIntList = map readInt . BS.words

getInt = readInt <$> BS.getLine
getIntList = readIntList <$> BS.getLine

calc :: [Int] -> Int -> [(Int, Int)]
calc [] _ = []
calc (n : ns) ma = (d, m) : calc ns ma
  where
    n' = ma - n
    d = n' `div` 2
    m = n' `mod` 2

main = do
  ns <- getIntList
  let ts = calc ns (maximum ns)
  let s = sum (map (\t -> fst t) ts)
  let s'
        | l == 0 = s
        | l == 1 = s + 2
        | l == 2 = s + 1
        where
          l = length (filter (\t -> snd t == 1) ts)
  print s'