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 would you like this order shipped ?  
 Person2:Send it by the fastest way .  
 Person1:        Are you going to ship this by air ? That might cost a little more .  
 Person2:How much ?  
 Person1:        I'll check the costs and call you back .  
 Person2:OK . 

formal