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:       Hello , Tom ! Do you have plans for this evening ?  
 Person2:Nothing special .  
 Person1:        How about having dinner with me ?  
 Person2:That's great . I would love to . And when ?  
 Person1:        Let ’ s fix it at seven o'clock , OK ?  
 Person2:No problem . However , maybe I should come early to help you prepare the dinner .  
 Person1:        Don ’ t worry . I will arrange everything .  
 Person2:All right , see you tonight .  
 Person1:        See you . 

informal