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:       Happy anniversary , sweetheart !  
 Person2:Yes . to our first anniversary and many more to come . Cheers !  
 Person1:        I'll drink to that . Thanks for making this a night worth remembering .  
 Person2:Well , it's a special day . They say if you survive the first year , the rest is smooth sailing .  
 Person1:        That's good to know . Oh , listen ! The band's playing our song .  
 Person2:I requested it . What do you say ? Do you have your dancing shoes on ?  
 Person1:        Always . 

informal