Definition: You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. You are required to assign a label 'formal' if there is an absence of emotion and a presence of questions anywhere within the conversation. If such pattern is not found assign the label 'informal'.
Input:  Person1:       My computer isn ’ t running at the same speed it used to be , it is testing my patience everyday . Can you tell me how to make it run faster ?  
 Person2:If you want to speed up your system , you ’ Ve got to clean it up first .  
 Person1:        How ?  
 Person2:You need to free your disk space . The simplest way is to use a Disk-Cleanup tool to remove temporary files and in store programs that you no longer use . Things should be fine next time you start . You also need to control what starts up . There is a program calls Start-up Delayer , It can help to set after how much time programs should be loaded after Windows boosts . For example , you can choose to set your Fox Mail program to load 30 seconds after Windows starts up .  
 Person1:        Very useful advice , I will try them right now . 

formal