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:       There will be a party in my company ; what shall I wear ?  
 Person2:Is it formal or informal ?  
 Person1:        I guess it is a formal one because the general director will give a speech there , and most of the staff will take part in .  
 Person2:In that case , formal suit with a nice tie will be better .  
 Person1:        You are right . What about shoes ?  
 Person2:The brown leather shoes are OK .  
 Person1:        Thanks a lot .  
 Person2:Don ’ t mention it . 

informal