When a $\pi^0$ decays into photons, the only possible number of photons to which it can decay is 2$\times n$, with $n$ a natural number. This is because in electromagnetic decays charge conjugation is conserved, let's assume that it decays into two photons
$$\pi^0 -> \gamma+\gamma$$
C|$\pi^0$> = 1
C|$\gamma$> = -1
in this decay, parity also needs to be conserved, and
P|$\pi^0$> = -1
P|$\gamma$> = -1
the parity of the system of two photons is given by $(-1)^l$P|$\gamma$>P|$\gamma$> where $l$ is the orbital angular momentum of the system. Does this mean that if parity is conserved, the orbital angular momentum of the resulting system must be $l=1$ (or 3, 5...) or am I deducing something wrong?