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:       S :: Welcome to Flash Foto.What can I do for you , ma ’ am ?  
 Person2:C :: I ’ d like to have this roll of film developed .  
 Person1:        S :: What size prints would you like ?  
 Person2:C :: Four by six will do .  
 Person1:        S :: All right , ma ’ am , they ’ ll be ready for you in an hour . 

formal