Sorcery
Shuffle
your
library.
As
many
times
as
you
choose,
you
may
exile
the
top
card
of
your
library.
If
the
total
mana
value
of
the
cards
exiled
this
way
is
13
or
less,
you
may
cast
any
number
of
spells
from
among
those
cards
without
paying
their
mana
costs.
