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 ’ d like to post this letter to Korea .  
 Person2:Is it urgent ? Would you like the express service ?  
 Person1:        No thank you . I ’ d like to send it just by normal post . 

formal