How to Hide ThumbPress Admin Menus

function plt_hide_image_sizes_menus() {
	//Hide "Tools → Scheduled Actions".
	remove_submenu_page('tools.php', 'action-scheduler');

	//Hide "ThumbPress".
	remove_menu_page('thumbpress');
	//Hide "ThumbPress → Modules".
	remove_submenu_page('thumbpress', 'thumbpress');
	//Hide "ThumbPress → Advanced Features".
	remove_submenu_page('thumbpress', 'upgrade-to-pro');
}

add_action('admin_menu', 'plt_hide_image_sizes_menus', 101);

Where do I put this code?