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:       How's the building work going ?  
 Person2:Well , I'm afraid we've had a slight delay .  
 Person1:        What's the problem ? We really can't have any delays at this stage . We're working to a really tight schedule and we're already over budget .  
 Person2:The cement arrived late but don't worry , I'm confident we can still meet the deadline . The crew is on stand-by and as soon as the concrete has set we can get started again .  
 Person1:        OK . Keep me informed . Jt must be ready on time . 

formal