How to Hide Jetpack Admin Menus

function plt_hide_jetpack_menus() {
	//Hide the "Jetpack" menu.
	remove_menu_page('jetpack');
	//Hide the "Appearance → Additional CSS" menu.
	remove_submenu_page('themes.php', 'editcss-theme-enhancements-redirect');
}

add_action('admin_menu', 'plt_hide_jetpack_menus', 1000);

Where do I put this code?