# coding:utf-8

A, B, S = map(int, input().split())
ans = 0
if abs(A-S) <= abs(B-S):
    # print('A')
    ans = abs(A-S)+S
# ここからB
elif S > A:
    # print('B')
    if A == 0:
        ans += 1
        A = 1
    ans += abs(B-S)+abs(A-S) + A
else:
    # print('else')
    ans = abs(B-S)+min(A+(S-1), abs(A-S)+A)
print(ans)

# if A < S and abs(A-S) > abs(B-S):
#     # print('B root')
#     if A == 0:
#         ans += 1
#     ans += abs(B-S) + abs(A-S) + A
# else:
#     print('A root')
#     ans = abs(A-S) + S
# print(ans)