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:       Shut up ... Billy ... BILLY !  
 Person2:What !  
 Person1:        Wow ! What's that ?  
 Person2:It's my new radio earphone .  
 Person1:        It's so small that I didn't notice it .  
 Person2:What were you screaming at me for ? 

informal