A, B, S = map(int, input().split())
dA, dB = abs(S - A), abs(S - B)

if S == 1 or dA <= dB:
    print(dA + S)
    exit()

if A == 0:
    print(dB + S + 1)
else:
    ans = dB + abs(S - A) + A
    ans = min(ans, dB + S - 1 + A)
    print(ans)