# Conservation of Baryon number for this proton decay

The conservation law requires that Baryon number be conserved; that is, the sum of the Baryon number before and after a reaction/ decay must always equal the sum of the Baryon number after the reaction. This sounds fairly simple and I thought I've understood it until an example from my text made me question my understand

$$p\rightarrow e^{+} + \pi^{0}$$ Why is this proton decay conserved?

I see that proton has a Baryon number of 1. Positron has a Baryon number of 0 and pion naught have a Baryon number of 0. Clearly, the Baryon number is not conserved. But an example from my notes says it is a conserved decay. What am I missing?