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:       Which is your preference , tea or coffee ? 
 Person2:My choice would always be tea . 
 Person1:        When did you form this hobby ? 
 Person2:Last year when I visited China . 

formal