diff --git a/lib/shortnr/url.ex b/lib/shortnr/url.ex
index 29453b5..390f5c6 100644
--- a/lib/shortnr/url.ex
+++ b/lib/shortnr/url.ex
@@ -53,7 +53,7 @@ defmodule Shortnr.URL do
     |> handle_errors
   end
 
-  @id_chars String.codepoints("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXWYZ0123456789")
+  @id_chars String.codepoints("abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXWYZ0123456789")
   @spec generate_id() :: String.t()
   def generate_id do
     for _ <- 0..7,