How to Hide the "Login NoCaptcha" Admin Menu

function plt_hide_login_recaptcha_menus() {
	//Hide the "Settings → Login NoCaptcha" menu.
	remove_submenu_page('options-general.php', 'login-recaptcha/admin.php');
}

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

Where do I put this code?