gistfile1.cs

var items = serviceInstance.FindItems(
       //Find Mails from Inbox of the given Mailbox
       new FolderId(WellKnownFolderName.Inbox, new Mailbox(ConfigurationManager.AppSettings["MailBox"].ToString())),
       //Filter criterion
       new SearchFilter.SearchFilterCollection(LogicalOperator.And, new SearchFilter[] {
       new SearchFilter.ContainsSubstring(ItemSchema.Subject, ConfigurationManager.AppSettings["ValidEmailIdentifier"].ToString()),
       new SearchFilter.IsEqualTo(EmailMessageSchema.IsRead, false)
       }),
       //View Size as 15
       new ItemView(15));