/* Whenever potential ambiguity in binary operator precedence may occur, 
 * parentheses must be used to clearly disambiguate the order in which these 
 * operators are applied. For example, the following expression constraint is 
 * not valid:
 */

<19829001|Disorder of lung| 
    OR ^900000000000538005|Description format reference set|  
    MINUS ^447562003|ICD-10 complex map reference set|