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:       Let me get last week's notes .  
 Person2:Yeah , sure , you didn't come to class that day ?  
 Person1:        I couldn't come .  
 Person2:Why not ?  
 Person1:        I wasn't feeling well .  
 Person2:Here they are .  
 Person1:        Thanks a lot ; are these all the notes ?  
 Person2:Oh , no , this is the rest .  
 Person1:        Thank you very much .  
 Person2:It's no problem at all . 

informal