diff --git a/rsa/Makefile b/rsa/Makefile
index 08a0c23..a280052 100644
--- a/rsa/Makefile
+++ b/rsa/Makefile
@@ -13,7 +13,7 @@ $(NAME):
 	gcc -Wall -Wextra -Werror -Wunused-function $(SRC) -o $(NAME)
 
 fast:
-	gcc -Wall -Wextra -Werror -Wunused-function -o3 $(SRC) -o $(NAME)
+	gcc -Wall -Wextra -Werror -Wunused-function -O3 $(SRC) -o $(NAME)
 
 profile:
 	gcc -Wall -Wextra -Werror -Wunused-function -pg $(SRC) -o $(NAME)