sub isogram {
#234567890#234567890#234567890#234567890#234567890
my%h=map{($_,1)}split//,$_[0];keys%h==length$_[0]
}

print "$_ is ", (isogram($_) ? '' : 'not '), "an isogram\n" for @ARGV;


##</code><code>##

sub isogram {
#23456789
/(.).*\1/
}

print "$_ is ", (isogram() ? '' : 'not '), "an isogram\n" for @ARGV;