A die has 9 faces, numbered from 1 to 9 and every number has the same chance of appearing. You roll the die and write the numbers down, one after another, and stop when you write down a multiple of 3. For example, suppose you roll 2 then 3 then 7. You would stop here, because 2 and 23 are not multiples of 3 but 237 is a multiple of 3. Find the expected number of rolls.