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:       Would you like something to eat ? 
 Person2:Thank you . No . I ’ m late for dinner at my house . I really have to go . 
 Person1:        Would you like to call home ? 
 Person2:I ’ d appreciate that . 
 Person1:        Please use the phone . 
 Person2:Thanks . 

informal