I'm trying to show a relationship of a number and its prime factors. The problem follows as:
Show if n >= 2 and n is not an element of the primes, there exists a prime number p such that p | n and p <= root n.
I'm coming near some kind of point to start from but can't make that initial step into it, any tips? Thanks.
An example of the problem

Since $n > 1$ is not prime, we may write $n = ab$ where $a,b > 1$ are positive integers. If both $a,b$ were greater than $\sqrt{a}$, then $ab > a$, a contradiction. Thus at least one is less than or equal to $\sqrt{n}$, say $a$, and by the Fundamental Theorem of Arithmetic $a$ is a product of primes, one of which is less than or equal to $\sqrt{n}$.