## [Retina], 13 bytes

    [][,]|\b2
    
    ^$

[Try it online!]

[Retina]: https://github.com/m-ender/retina
[Try it online!]: https://tio.run/nexus/retina#U9VwT/gfHRutE1sTk2TExRWn8v9/tFEsV7SRDogEMnXATDAPJADkxwJpQ5ASqDogBHGjDSHqAA "Retina – TIO Nexus"