<Table> <Tr> <Th colspan="2"> Ruby slippers </Th> </Tr> <Tr> <Td colspan="2"> One of the pairs used in The Wizard of Oz ( 1939 ) , on display at the Smithsonian Institution National Museum of American History </Td> </Tr> <Tr> <Th colspan="2"> Plot element from The Wizard of Oz </Th> </Tr> <Tr> <Th> Publisher </Th> <Td> Metro - Goldwyn - Mayer </Td> </Tr> <Tr> <Th> First appearance </Th> <Td> The Wizard of Oz ( 1939 ) </Td> </Tr> <Tr> <Th> Created by </Th> <Td> Gilbert Adrian ( costume design ) </Td> </Tr> <Tr> <Th> Genre </Th> <Td> Fantasy fiction </Td> </Tr> <Tr> <Th colspan="2"> In - story information </Th> </Tr> <Tr> <Th> Type </Th> <Td> Magical slippers </Td> </Tr> <Tr> <Th> Function </Th> <Td> Able to send Dorothy Gale back home to Kansas after clicking the heels three times </Td> </Tr> </Table>
how many times does dorothy have to clink her ruby slippers together to get home
three