How to call SQL procedure in c# without parameters

Question

I made a table whrere from I want to get sum of total days (din) group by PtR number. here is query:

ALTER PROCEDURE getdays
@tr_ptr nvarchar(6), @tr_din nvarchar(2), @Total int output
AS
BEGIN
SELECT Total = SUM (CONVERT(int, tr_din)) FROM Treatments GROUP BY tr_ptr
END

I want to get sum result in my label of form by clicking the button, please guide me how to complete this job