what namespace first two call system or custom made c# code example
Example: HOW TO CALL AN EXTENSION METHOD FOR VIEW C#
<pages>
<namespaces>
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Routing" />
<add namespace="System.Linq" />
<add namespace="System.Collections.Generic" />
<add namespace="MyProject.Extensions" />
</namespaces>
</pages>