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:       I'm calling about our appointment . I can't call on you this evening.My wife is terribly ill .  
 Person2:Sorry to hear that .  
 Person1:        How about next week ?  
 Person2:Fine , we'll be expecting you then . 

informal