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:       OK , so this is our newest machine . It was only installed last year .  
 Person2:What's the running speed of the machine ?  
 Person1:        About 1,500 metres per minute . It's one of the fastest in the world . We had a few problems with it after start-up but it's running very well now .  
 Person2:And what's the maximum output ?  
 Person1:        If we're running at full capacity , it's 160,000 tonnes per annum . 

formal