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:       Has the train come yet ?  
 Person2:No , I ‘ Ve been waiting for ages .  
 Person1:        It ’ s so unreliable . I ’ Ve been late for my meetings all this week .  
 Person2:Yes , me too . I think I ’ Ve lost some important clients recently because of this train !  
 Person1:        Yes , my customers have started to complain too !  
 Person2:Oh look ! Here it comes now ! 

informal