<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> <Tr> <Th_colspan="2"> Ruby slippers </Th> </Tr>

How many times does dorothy have to clink her ruby slippers together to get home