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 don't know whether or not to believe him .  
 Person2:You can trust him . He always tells the truth .  
 Person1:        But it's really too important to me .  
 Person2:I said you can trust him . You just have to believe it . 

informal