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:       David , would you like something to eat ?  
 Person2:No , I'm full .  
 Person1:        Do you want something to drink ?  
 Person2:Yes , I'd like some coffee .  
 Person1:        Sorry , I don't have any coffee .  
 Person2:That's OK . I'll have a glass of water .  
 Person1:        A small glass , or a big one ?  
 Person2:Small please .  
 Person1:        Here you are .  
 Person2:Thanks .  
 Person1:        You're welcome . 

informal