diff --git a/README.md b/README.md
index 6c0d4b8..fcbe498 100644
--- a/README.md
+++ b/README.md
@@ -36,9 +36,10 @@ server {
 }
 ```
 
-Caching based only on file id can be enabled with this example configuration
+(Optional) Caching based only on file id can be enabled with this example configuration
 ```cfg
-location ~ ^/-([a-zA-Z0-9]+) {
+# Will match '/-{id}' '/-{id}/' '/-{id}/name' but not '/-{id}/name/other'
+location ~ ^/-([a-zA-Z0-9]+)(?:/?$|/[^\/]+$)
     # Other caching options are omitted here...
     proxy_cache_revalidate on;
     proxy_cache_key "$host$1";