for(@p=$n=2;$#p<20;$n++,$g=1){
for(@p){$g=0,last if!($n%$_);
}push@p,$n if$g;}$c{$_}=$c++for
'A'..'Z';($d=join'',)=~
s/\s+//g;print(('A'..'Z')[($c{
substr($d,$_,1)}+5)%26])for@p;

__DATA__
XUEPXNO OJZYVKI ZDJ     JPOA
   C    A       C  S    L   X
   X    D       Z   R   M   Y
   I    KPEKDFG Z   J   MPNG
   G    G       P   N   G
   N    C       S  V    U
   X    CVKXREK RHF     N

TIZSMUJGJIJWZIFNRHCNMMOQWIRNO