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:       Excuse me . My name is David Walker . Haven't we met before ?  
 Person2:Well , let me see ... Do you work at IBM Corporation ?  
 Person1:        Yes , I do .  
 Person2:Now I remember . We met at a conference in Tokyo last year . 

formal