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:       Don't you think we ' d leave for the concert now ?  
 Person2:What time dose it start ?  
 Person1:        In about 25 minutes .  
 Person2:Then we'd better get started . 

formal