ENTER THE NUMBER 10,20, THEN 30                                                 
? 10                                                                            
AN ERROR HAS JUST OCCURRED IN LINE 50                                           
ENTER THE NUMBER 10,20, THEN 30                                                 
? 20                                                                            
AN ERROR HAS JUST OCCURRED IN LINE 60                                           
ENTER THE NUMBER 10,20, THEN 30                                                 
? 30                                                                            
AN ERROR HAS JUST OCCURRED IN LINE 70                                           
ENTER THE NUMBER 10,20, THEN 30                                                 
? 1                                                                             
THE NUMBER 1 DID NOT CAUSE AN ERROR                                             
ENTER THE NUMBER 10,20, THEN 30                                                 
? 31                                                                            
THE NUMBER 31 DID NOT CAUSE AN ERROR                                            
ENTER THE NUMBER 10,20, THEN 30                                                 
? 0                                                                             
THE NUMBER 0 DID NOT CAUSE AN ERROR                                             
ENTER THE NUMBER 10,20, THEN 30                                                 
? -1                                                                            
