diff --git a/util.py b/util.py
index a32c28f..b0f87c1 100644
--- a/util.py
+++ b/util.py
@@ -1,4 +1,4 @@
 
 def is_valid_id(s: str):
-    return all(c.isalnum() or c in "_-" for c in s)
+    return all(c.isalnum() or c in "_-" for c in s) and 16 >= len(s) >= 3