Nothing, technically Dan. Sorry about this.
It is an intro course and being a bit restrictive with the solutions is okay. Well, more so. Commas in a for weren't taught.
You're right, well close--you have no space before month, but even when fixed it's not accepted--yet this being an intro course to me means outlier solutions like this should be dealt with here.
Definitely when you get to JSRT 3 especially post stuff like this, as in that course we should for many reasons try to accept a wider variety of solutions.
This probably won't be fixed, definitely not soon, but thanks for posting!