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:       Good morning . I'd like to buy 2 tickets .  
 Person2:Have you brought your student card ?  
 Person1:        I didn't know you have student tickets so I left them in my bag .  
 Person2:In that case , you have to buy two full fare tickets .  
 Person1:        Here is the money . 

formal