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:       Welcome , Li Mei . Please give me your coat and hat .  
 Person2:Thank you , Peter .  
 Person1:        Oh , let's come in and enjoy yourself .  
 Person2:Happy birthday , Peter , and many happy returns of the day . Here's a present for you .  
 Person1:        Thank you , Li Mei . Come into the dining room . I'm going to cut the cake soon .  
 Person2:What wish do you make ?  
 Person1:        It's a secret . 

informal