Let $n>1$, then prove that $1+ 1/2+1/3+\cdots+1/n$ is not an integer.

Question

Possible Duplicate:
Is there an elementary proof that $\sum \limits_{k=1}^n \frac1k$ is never an integer?

Let $n>1$, then prove that $\;1+\dfrac{1}{2}+\dfrac{1}{3}+\cdots +\dfrac{1}{n}\;$ is not an integer.

Thanks