  Entanglement-assisted quantum error correcting codes (EAQECCs) constructed
from Reed-Solomon codes and BCH codes are considered in this work. It is
provided a complete and explicit formula for the parameters of EAQECCs coming
from any Reed-Solomon code, for the Hermitian metric, and from any BCH code
with extension degree $2$ and consecutive cyclotomic cosets, for both the
Euclidean and the Hermitian metric. The main task in this work is the
computation of a completely general formula for $c$, the minimum number of
required maximally entangled quantum states.
