a,b,s = map(int,input().split())
ans = 0
if s == 1 or abs(a-s) <= abs(b-s):
    ans = abs(a-s) + s
else:
    if a:
        ans = abs(b-s) + min(s-1+abs(a-s)+s,abs(a-s)+abs(a))
    else:
        ans = abs(b-s) + s + 1
print(ans)