NEED HELP figuring out the name of this manga?

i while back i started to read this manga, but my computer crashed and i could not remember alot of manga and anime titles. i vaguely remember it beginning with her being on a bus/train, and rudely kicking an old man who appeared to be sleeping, but was actually trying to steal from the person next to him. but everybody misunderstood and thought she was just being rude. she was transferring from a high cl school(i think) so everybody avoided her because she acted differently. she was on the rooftop and started singing a hymnal and a boy heard and found her. i cant remember much more than this. i suddenly remembered this manga this evening and got interested again but i couldn't remember the name.i hope somebody can help.