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:       Switchboard . Which extension would you like ?  
 Person2:Extension 1616 , please .  
 Person1:        I'm afraid the line is busy at the moment . Just hold on , please .  
 Person2:Then , will you try extension 235 ?  
 Person1:        Certainty , sir . 

formal