$j = jQuery.noConflict();

function mainmenu(){
$j(" #nav ul "). css({display: "none"});
$j(" #nav li").hover(function(){
$j(this).find('ul:first').css({visibility: "visible",display: "none"}).slideDown(200);
},function(){
$j(this).find('ul:first').css({visibility: "hidden"});
});
}

$j(document).ready(function(){
mainmenu();
});