diff --git a/README.md b/README.md
index 29b1684..df77369 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ A simple CAPTCHA service implementation.
 
     justcaptchad -expiry 5m -listen /var/run/justcaptchad/j.sock
 
-`-expiry` takes time for CAPTCHA to be valid for in format XX{s,m,h}.
+`-expiry` takes time for CAPTCHA to be valid for in format X{s,m,h}.
 
 `-listen` is `ip:port` or `/path/to/unix.sock` to listen on.