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:       What can I do for you ?  
 Person2:Yes . There is something wrong with my watch . It stopped several hours ago .  
 Person1:        Let me have a look . Oh , the watch ’ s battery is worn down .  
 Person2:How much is a battery ?  
 Person1:        $ 50 .  
 Person2:How long will it last ?  
 Person1:        About 2 years .  
 Person2:Here is the money . 

formal