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 OCaml (4.02.3) (judge verdict: Accepted)

let () =
  let a,b,c = Scanf.scanf "%d %d %d " (fun a b c -> a,b,c) in
  let l = [a;b;c] in
  let ls = List.sort compare l in
  let d2 = (List.nth ls 2) - (List.nth ls 0) in
  let d1 = (List.nth ls 2) - (List.nth ls 1) in

  Printf.printf "%d\n" @@
  if (d2+d1) mod 2 = 0 then (d2+d1)/2 else 2+((d2+d1)/2)