diff --git a/beautiful-racket-demo/basic-demo-3/parser.rkt b/beautiful-racket-demo/basic-demo-3/parser.rkt
index dbbce00..1aba3f9 100644
--- a/beautiful-racket-demo/basic-demo-3/parser.rkt
+++ b/beautiful-racket-demo/basic-demo-3/parser.rkt
@@ -33,6 +33,6 @@ b-product : [b-product ("*"|"/"|"mod")] b-neg
 b-neg : ["-"] b-expt
 b-expt : [b-expt ("^")] b-value
 @b-value : b-number | b-id | /"(" b-expr /")" | b-func
-b-func : b-id /"(" b-expr [/"," b-expr]* /")"
+b-func : ID /"(" b-expr [/"," b-expr]* /")"
 @b-number : INTEGER | DECIMAL
 b-repl : (b-statement | b-expr) (/":" [b-repl])*
\ No newline at end of file