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:       Would you like this one ?  
 Person2:I don't think that will do . How about the one at your back ?  
 Person1:        This one ?  
 Person2:No , the other one ... yes .  
 Person1:        This one is especially built for hard , continuous play . And every detail of workmanship and material has been carefully checked to make it a dependable one for tournament use .  
 Person2:It do look beautiful . Well . I think I'll take it.Now do you have any racket covers ?  
 Person1:        This cover comes with the racket .  
 Person2:How much does it come up to ?  
 Person1:        The mark says six hundred yuan , plus tax , it's six hundred and eighty yuan .  
 Person2:Do you accept credit cards ?  
 Person1:        Sure . If you'll just wait here , I'll be right with you in a minute . 

formal