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:       Some people are always closing their handsets , so it's difficult to inform them .  
 Person2:Why not send them short messages ?  
 Person1:        Can short messages reach them ?  
 Person2:Short messages will be kept in the short messages center . Once they open the handsets they will receive them , which is better than you can't find them .  
 Person1:        Why haven't I thought of this skill ?  
 Person2:I use short messages quite a lot . If it's not too complicated I will send a short message , which can save much phone charge .  
 Person1:        I am informed that many people used short messages to pay a New Year call , and only on the Spring Festival it amounted to 1 billion this year , didn't it ?  
 Person2:I almost can't live without messages , from which I learn about weather forecasts and stock quotations . 

informal