Find the sum of all elements in the set of units U(Z8)={x∈Z8:gcd(x,8)=1}U(\mathbb{Z}_8) = \{x \in \mathbb{Z}_8 : \gcd(x, 8) = 1\}U(Z8)={x∈Z8:gcd(x,8)=1}.
888
161616
444
000