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:       Mandy , Would you like to come for dinner tonight ?  
 Person2:Dinner ? Where ?  
 Person1:        At the new Five Spices restaurant in Chaoyang .  
 Person2:What kind of food do they serve ?  
 Person1:        It ’ s Asian fusion . I heard it ’ s delicious .  
 Person2:Oh really ! That sounds lovely . 

informal