And later on talking to Chuck, we realised that if we had a cell phone component, if you could send an SMS into our service whenever you split a bill, you wouldn't even have to carry that book around. 后来我跟恰克聊了这件事,我们意识到如果把手机也包含进来,那么,每当你想分摊账目的时候只要发个短信就可以了,连记事本都省了。