How to Hide Ninja Charts Admin Menus

function plt_hide_ninja_charts_menus() {
	//Hide "Ninja Charts".
	remove_menu_page('ninja-charts');
	//Hide "Ninja Charts → Charts".
	remove_submenu_page('ninja-charts', 'ninja-charts');
	//Hide "Ninja Charts → Add Chart".
	remove_submenu_page('ninja-charts', 'ninja-charts#/add-chart');
	//Hide "Ninja Charts → Get help".
	remove_submenu_page('ninja-charts', 'ninja-charts#/support');
}

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

Where do I put this code?