It's a variation of the song Ohayoo! I honestly think this one is just as wonderful. Enjoy!
Btw it plays in episode 9 when Yui says "please protect me" to Aoki, in fact that's what the title means, I think... idk go to google translate. Anyway, enjoy!
I DO NOT OWN THE SONG NOR THE IMAGES. IT ALL BELONGS TO THEIR RESPECTIVE OWNERS