$A$ pair of six-sided dice are labeled so that one die has only even numbers (two each of $2, 4$, and $6$), and the other die has only odd numbers (two of each $1, 3$, and $5$). The pair of dice is rolled. Find the probability that the sum of the numbers on the tops of the two dice is $7$. Express your answer in the form \(\frac{k}{m}\) and provide the value of \(k + m\).

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