intro(pre chorus):
e ------------------------------|
b ------------------------------|
g ------------------------------|
D 3-3-3-/-7-5-5-5-/-7-7-7-\-4-4-|  3x
A 5-5-5-/-5-3-3-3-/-5-5-5-\-2-2-|
E ------------------------------|

e ------------------------------|
b ------------------------------|
g ------------------------------|
D 5-5-5-5-/-7-(7)---------------|  1x ( ) means change from pre chorus to
A 3-3-3-3-/-5-(5)---------------|         chorus stroke as many times as
E ------------------------------|         needed (not fin yet)