How to Hide the "Adcovery" Admin Menu

function plt_hide_adcovery_menus() {
	//Hide the "Settings → Adcovery" menu.
	remove_submenu_page('options-general.php', 'adcovery_admin_page');
}

add_action('admin_menu', 'plt_hide_adcovery_menus', 11);

Where do I put this code?