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:       Can I have this roll of film developed here ?  
 Person2:Sure . Let's see it .  
 Person1:        Here you are .  
 Person2:What size of prints would you like to have ?  
 Person1:        Regular will be fine . How long will it take ?  
 Person2:Only four hours .  
 Person1:        Good . I'll come back in the evening . 

formal