if ($probability->{positive} > $probability->{negative} and
    $probability->{positive} > $probability->{neutral}) {
    print "positive: $sentence\n";
}
elsif ($probability->{negative} > $probability->{positive} and
    $probability->{negative} > $probability->{neutral}) {
    print "negative: $sentence\n";
}
elsif ($probability->{neutral} > $probability->{positive} and
    $probability->{neutral} > $probability->{negative}) {
    print "neutral: $sentence\n";
}