I9300 - root on new/old phone topic

Hello everyone.
I bought yesterday used SGS III I9300.
My previously phones was allways HTC, so it`s new for ne. I want to make root.
Here is info from device:
Model version: I9300XXELKC
Android: 4.1.2
kernel:3.03.3
Model number: JZO54K.I9300XXELKC
What is the best way to do it? I don`t know history of this phone.
Regards