Correction: The utilitarians are a kind of combination of Epicurus and a certain aspect of Christianity, not Kant as such. Epicurus was a hedonist. He advocated that the standard of moral value is happiness. Christianity, among other things, advocates "love thy neighbor as thyself." If one puts the two together one gets that the standard of moral value is your neighbor's pleasure or as the utilitarians usually put it, "the greatest happiness of the greatest number." Of course one is allowed to count one's own pleasure but only as one among all the others.