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 sorry , I'm engaged at 2 p . m .  
 Person2:If you don't mind , let's make it a little later.What about three or four ?  
 Person1:        Sorry , the whole afternoon is filled up here.Will tomorrow do ?  
 Person2:All right . 

informal