A, B, S = map(int, input().split())

ans = 0

if abs(A-S) <= abs(B-S) or S == 1:
    ans = abs(A-S) + S

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

print(ans)