How to Hide the "Syntax Highlighter Pro" Admin Menu

function plt_hide_syntaxhighlighterpro_menus() {
	//Hide the "Settings → Syntax Highlighter Pro" menu.
	remove_submenu_page('options-general.php', 'wp-syntaxhighlighterpro.php');
}

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

Where do I put this code?