Negative Fibonacci Numbers You probably all know the fibonacci sequence:

fibonacci(n)=fibonacci(n-1)+fibonacci(n-2)
fibonacci(0)=0
fibonacci(1)=1


Your task is as simple as it could be:


Given integer N compute fibonacci(n)


but here is the twist:


Also do negative N


Wait. What?

fibonacci(1)=fibonacci(0)+fibonacci(-1)


so

fibonacci(-1)=1


and

fibonacci(-2)=fibonacci(0)-fibonacci(1)=-1


and so on...


This is a code-golf so shortest programm in bytes win.
You may submit a function or a full programm
N is in [-100,100]


Testcase(s) in CSV:

-9;-8;-7;-6;-5;-4;-3;-2;-1;0;1;2;3;4;5;6;7;8
34;-21;13;-8;5;-3;2;-1;1;0;1;1;2;3;5;8;13;21


Hint:


   n&lt;0 and n&amp;1==0:
 fibonacci(n)=fibonacci(abs(n))*-1
Mathematica, 9 bytes

Fibonacci


Yes, this built-in function supports negative numbers.