# CJam, 33 bytes

    q~:i\fb:~0+2/W<Gfb:c' ,-'ÿ),127>-

Takes input in the form `6 "Hello, World!"`. [Test it here.][1]

 [1]: http://cjam.aditsu.net/#code=q~%3Ai%5Cfb%3A~0%2B2%2FW%3CGfb%3Ac'%20%2C-'%C3%BF)%2C127%3E-&input=6%20%22Hello%2C%20World!%22