8. Let $n, m$ be positive integers, for any sufficiently small positive number $a$, if $n>m$ is a sufficient and necessary condition for $\frac{1}{n}<a$, then the relationship between $m$ and $a$ is $m=$ $\qquad$ .
$\frac{1}{n}\frac{1}{a} \Rightarrow n \geqslant\left[\frac{1}{a}\right]+1$, so $m=\left[\frac{1}{a}\right]$.