소프티어

import sys

row = []

result_list = []

for i in range(3):

  row = list(map(int, input().split()))

  result_list.append(row)

result = 0 

min = 9999

#########################################

for i in range(len(result_list)):

  row = result_list[i]

  if len(set(row)) == 1:

    min = 0 

    break;

  else:

    base = row[0]

    for value in (row):

      if value != base:

        if abs(base-value) < min:

          min = abs(base-value)

for col in range(3):

  col_value = [row[col] for row in result_list]

  if len(set(col_value)) == 1:

    min = 0 

    break;

  else:

    base = col_value[0]

    for value in (col_value):

      if value != base:

        if abs(base-value) < min:

          min = abs(base-value)

print(min)