I tried below formula.. but not working..

=or(countif($A:$a,A3)=1,countif($e:$e,A3)=1,coun tif($i:$i,A3)=1,
countif($m:$m,A3)=1,countif($q:$q,A3)=1,countif( $u:$u,A3)=1,
countif($y:$y,A3)=1,countif($ac:$ac,A3)=1,counti f($ag:$ag,A3)=1,
countif($ak:$ak,A3)=1,countif($ao:$ao,A3)=1,coun tif($as:$as,A3)=1,
countif($aw:$aw,A3)=1,countif($ba:$ba,A3)=1)