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:       And lightweight , too . It'll play for 20 hours on two AA batteries !  
 Person2:Cool ! The sound is great . These earphones are awesome !  
 Person1:        And they're really safe . They'll protect your ear from sound damage .  
 Person2:You certainly need that . You always pump the volume up way too high .  
 Person1:        I know . And you can also hear outside noises while you listen to music .  
 Person2:You're right ! So I can listen to music while riding my motorbike ! 

informal