How to Hide Smush Admin Menus

function plt_hide_wp_smushit_menus() {
	//Hide "Smush".
	remove_menu_page('smush');
	//Hide "Smush → Dashboard".
	remove_submenu_page('smush', 'smush');
	//Hide "Smush → Bulk Smush".
	remove_submenu_page('smush', 'smush-bulk');
	//Hide "Smush → Directory Smush".
	remove_submenu_page('smush', 'smush-directory');
	//Hide "Smush → Lazy Load".
	remove_submenu_page('smush', 'smush-lazy-load');
	//Hide "Smush → CDN".
	remove_submenu_page('smush', 'smush-cdn');
	//Hide "Smush → Next-Gen Formats".
	remove_submenu_page('smush', 'smush-next-gen');
	//Hide "Smush → Integrations".
	remove_submenu_page('smush', 'smush-integrations');
	//Hide "Smush → Settings".
	remove_submenu_page('smush', 'smush-settings');
	//Hide "Smush → Tutorials".
	remove_submenu_page('smush', 'smush-tutorials');
	//Hide "Smush → More free Plugins?".
	remove_submenu_page('smush', 'smush-cross-sell');
	//Hide "Smush → Upgrade for 80% Off!".
	remove_submenu_page('smush', 'https://wpmudev.com/project/wp-smush-pro/?utm_source=smush&utm_medium=plugin&utm_campaign=smush_submenu_upsell');
}

add_action('admin_menu', 'plt_hide_wp_smushit_menus', 11);
Where do I put this code?