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 Python (3.4.3) (judge verdict: Accepted)

A = sorted(list(map(int, input().split())))
ans = 0

while len(set(A))>1:
    if A[2] > A[0]+1:
        A[0] += 2
    elif A[1] == A[2] and A[0] == A[1]-1:
        A[1] += 1
        A[2] += 1
    elif A[0]== A[1] and A[1] == A[2]-1:
        A[0] += 1
        A[1] += 1
    elif A[0] < A[1]:
        A[0] += 2
    ans += 1
    A.sort()

print(ans)