Many many many Numbers

$P(x)$ is a polynomial of degree 1998 such that $P(k)$ = $\frac{1}{k}$ for 1 , 2 , 3 , …… , 1999. The value of $P(2000)$ is

(1) $\frac{1}{1000}$ (2) $\frac{1}{999}$ (3) $\frac{1}{2000}$ (4) $\frac{1}{1999}$ (5) $\frac{1}{4000}$

add: if you know how to do it , please write it down! :)