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:       Anna , Would you like to dance ?  
 Person2:I ’ d love to , but I ’ m a terrible dancer . I ’ m afraid I may step on your toes .  
 Person1:        Don ’ t worry about it . I ’ ll show you how . It ’ s a piece of cake .  
 Person2:Thank you . I ’ ll try my best . 

informal