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:       How was the party last night ? Did you enjoy it ?  
 Person2:Oh , don ’ t talk to me about last night ! It was the most awful evening I ’ Ve ever had .  
 Person1:        Why ? What happened ?  
 Person2:Well . Mary had promised to be my date , but she stood me up . I waited for her for a full hour in the cold wind .  
 Person1:        What about the party ?  
 Person2:It was boring . The music was too slow and the food was lousy and , above all , I was really sick of the same old crowd all the time .  
 Person1:        So how long did you stay ?  
 Person2:I left after the opening dance . I couldn ’ t wait to get out of there . 

informal