update readme and example program

1 files changed, 1 insertions, 0 deletions

diff --git a/README.md b/README.md
index 307b5c5..063b162 100755
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@ For a sample implementation, check the [Example](https://github.com/sendgrid/sen
 
 Add the following namespaces to use the library:
 ```csharp
+using System;
 using System.Net;
 using System.Net.Mail;
 using SendGridMail;