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:       Excuse me . But are you Mrs . Smith from America ?  
 Person2:That's it . I am Maria Smith . You must be Zhang Lin from Tianjin Sports Facility Co.Ltd .  
 Person1:        Yes . Nice to meet you , Mrs Smith .  
 Person2:Nice to meet you too , Mr . Zhang . 

informal