Asymetric graph with three nods

[Tom83B]

Why isn't this graph:
1-2 3
asymetric?
I think there exists only one automorphism:
2-1 3
but I'm also supposed to prove that ther are no asymetric graphs with 1<|V(G)|<=5
so it can't be asymmetric

 

[Tom83B]

Oh I see now! It can have no non-trivial symmetries and permutation (1 2) is already a non-trivial symmetry.
Sorry to bother