I have the following to prove :

Let $\phi$ and $\Phi$ denote the standard normal density and distribution functions respesctively. Prove that $$\lim_{x\to\infty}{1-\Phi(x)\over \phi(x)/x}=1$$

I am not being able to start. $\Phi$ is basically $\int \phi(x)dx$. How to calculate the limit?