# coding: UTF-8
import sys
#sys.setrecursionlimit(n)
import heapq
import re
import bisect
import random
import math
import itertools
from collections import defaultdict, deque
from copy import deepcopy
from decimal import *

a, b, c = map(int, input().split())
count = 0
a += 1
b += 1
c += 1
aa = abs(a - c)
bb = abs(b - c)
if c == 2:
    count += abs(a - 2) + 1
elif aa > bb:
    if b >= c:
        count += b - 2
    else:
        count += bb + c - 2
    if a > c:
        count += abs(a - 2)
    count += 1
else:
    if a >= c:
        count += a - 2 + 1
    else:
        count += aa + c - 2 + 1
print(count)