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:       Simon , may I introduce you to Linda ? You don ’ t know each other , do you ?  
 Person2:No . I ’ Ve not had the pleasure of meeting her yet .  
 Person1:        How do you do ? I ’ m pleased to meet you .  
 Person2:How do you do ?  
 Person1:        Please sit down . Help yourself just like you are at home .  
 Person2:What would you like to drink ?  
 Person1:        A cup of coffee , please . 

informal