First riff 

G |—————————————————————————————
D |—————————————————————————————
A |0 0  0 3 3   2 2  2 1————————
E |———————————————————————2 1———   
Second riff (same as the first one but up an octave)
G |2 2  2 5 5   4 4  3 2———————————————————————————————————————————————|
D |———————————————————————3 2——————————————————————————————————————————|
A |————————————————————————————————————————————————————————————————————|
E |————————————————————————————————————————————————————————————————————|

when mereba is on it cuts out some notes but otherwise it switches between these two lines 


There is something different at the end that i havent quite figured out yet but this will get you through basically the entire song