hello number theorists ,

I'm beginner and I have troubles with this lemma which i belive it is true ,

let $\displaystyle p$ a prime number greater than $\displaystyle $3$$, and let $\displaystyle P$ be the set of primes less than $\displaystyle p$, show that there exist $\displaystyle p_1 , p_2 ... ,p_n$ from $\displaystyle P$, such that $\displaystyle p$ divides $\displaystyle \prod_{i=1}^{i=n} p_i -1$

Thanks in ADvance