How to Hide the "Smart Contact Button" Admin Menu

function plt_hide_web_solution_smart_contact_button_menus() {
	//Hide the "Settings → Smart Contact Button" menu.
	remove_submenu_page('options-general.php', 'web-solution-smart-contact-button');
}

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

Where do I put this code?