Hi,

I need help with the following question in Euler's theorem:

Let me be a positive integer with m≠2. If {r1,r2,…..,rΦ(m)} is a reduced residue system modulo m, prove that

r1 + r2 + …….. r3 Ξ 0 mod n

If it helps, the back of the book tells me to use this lemma:

Let m > 2. If a is a positive integer less than m with (a,m) = 1, then (m-a, m) =1

Any help is appreciated