How to Hide Gtbabel Admin Menus

function plt_hide_gtbabel_menus() {
	//Hide "Gtbabel".
	remove_menu_page('gtbabel-trans');
	//Hide "Gtbabel → Translations".
	remove_submenu_page('gtbabel-trans', 'gtbabel-trans');
	//Hide "Gtbabel → Language picker".
	remove_submenu_page('gtbabel-trans', 'gtbabel-lngpicker');
	//Hide "Gtbabel → Settings".
	remove_submenu_page('gtbabel-trans', 'gtbabel-settings');
	//Hide "Gtbabel → Setup wizard".
	remove_submenu_page('gtbabel-trans', 'gtbabel-wizard');
}

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

Where do I put this code?