$a,b,c,d$ such that $a^n=b^n=c^n=d^n=1$ and $a+b+c+d=1$

Natural number $n$ is said to be Beautiful if there exists four complex number $a,b,c,d$ such that
$a^n=b^n=c^n=d^n=1$ and $a+b+c+d=1$ . Show that there exists beautiful number and explain whether 28 is beautiful or not

I’m more concerned with how I can derive this problem