--- parser.y.orig	2004-04-07 09:44:36.000000000 -0400
+++ parser.y	2003-01-04 19:08:59.000000000 -0500
@@ -1964,7 +1964,7 @@
 		  /* Y_INT '-' Y_INT */
 		  if ($2.i >= 0)
 		    yyerror ("Syntax error");
-		  $$.i = $1.i - $2.i;
+		  $$.i = $1.i + $2.i;
 		}
 	;