diff --git a/beginner/apps/Cargo.toml b/beginner/apps/Cargo.toml
index 6c75a25..a5483c0 100644
--- a/beginner/apps/Cargo.toml
+++ b/beginner/apps/Cargo.toml
@@ -18,7 +18,7 @@ debug = 1
 debug-assertions = true # !
 incremental = false
 lto = "fat"
-opt-level = 0
+opt-level = 'z' # !
 overflow-checks = false
 
 [profile.release]