use v6;

sub prob12 (@a) {
    @a.map: {
        $_.isa(Array) ?? $_[1] xx $_[0] !! $_;
    }
}

my @l = ([4,'a'],'b',[2,'c'],[2,'a'],'d',[4,'e']);

say ~@l;
prob12(@l).perl.say;

# vim:filetype=perl6