This entire song can be played on the A string. It’s only 3 notes for the bass. 

Intro
G--------------------------------------------------
D--------------------------------------------------
A---{guitar}---------------8-------888888-----------
E---------------------------------------------------
Verse 
G--------------------------------------------------
D--------------------------------------------------
A-----888888-66—888888-66--------------------------
E---------------------------------------------------
Chorus (I think it’s the chorus, but its just a different part)
G------------------------------------------------------------------
D-------------------------------------------------------------------
A-----444444--6666666----8--4--6---8--4--6---8--4--6---8--4--6------
E-------------------------------------------------------------------