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:       Hi , can I help you ?  
 Person2:Yes , please . I'm looking for a sofa .  
 Person1:        What about this one ?  
 Person2:May it be used as a sofa in the day and a bed during the night ?  
 Person1:        Oh , you want a convertible sofa . This way , please . Over there is the one you want . 

formal