Horses X, Y, and Z are entered in a three-horse race in which ties are not possible. If the odds against X winning are $3\text{-to-}1$ and the odds against Y winning are $2\text{-to-}3$, what are the odds against Z winning? Express your answer in the form $k\text{-to-}m$. Please provide the value of k + m.

Let's think step by step and output the final answer within \boxed{}.
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