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:       Could you call Mr . Jacob for me , Sara ? I need to go over some stuff with him .  
 Person2:Of course , Mr . Roberts . But , could you tell me his extension number again ? I haven ’ t got all the numbers down yet .  
 Person1:        Sure , it ’ s 4-8- 7-2 . Don ’ t worry . You ’ re doing a fine job .  
 Person2:Thank you very much . Mr . Roberts . 

informal