How to Hide the "Easy PHP Settings" Admin Menu

function plt_hide_easy_php_settings_menus() {
	//Hide the "Tools → Easy PHP Settings" menu.
	remove_submenu_page('tools.php', 'easy-php-settings');
}

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

Where do I put this code?