Find the number of chains that can be prepared using 5 different coloured beads

Given 5 different coloured beads

Number of chains that can be prepared using 5 different coloured beads

$\Rightarrow \frac{1}{2}(n-1)!$

SZS$\Rightarrow \frac{1}{2}(5-1)!\Rightarrow \frac{1}{2}\times 4!$.