Dialog between two friends,<br/>M: Hi bro, I want to upgrade my mobile's operating system from 2.3.7 to<br/> 4.0 version.<br/><br/>Q: That's a better idea.<br/><br/>M: But I don't know how to do this..<br/> Will you help me?<br/>Q: Oh, sure. Why not.<br/><br/>Thanks, teachers