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:       What a nice tie you are wearing !  
 Person2:Thank you.But does it really look all right ?  
 Person1:        Certainly.It matches your suit perfectly .  
 Person2:Then does it go well with my sweater ?  
 Person1:        Yes.You look very smart today .  
 Person2:Thank you very much . 

informal