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:       Hi , Bob ! How are you doing ?  
 Person2:Fine ! How are you ?  
 Person1:        I'm fine too , thank you .  
 Person2:I've come to tell you I'm going to the concert this evening.Will you come with me ? I've two complimentary tickets .  
 Person1:        With the greatest pleasure.Where is the concert this evening ?  
 Person2:It will be held at the Music Hall .  
 Person1:        What's on the program ?  
 Person2:It's a piano recital . I'm fond of piano , you know . 

informal