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 really sick of waiting for a bus .  
 Person2:Yeah.Especially when you have something urgent to do .  
 Person1:        But a taxi costs too much .  
 Person2:That's true . 

informal