How to read stored procedure out put value in ado.net

create proc Authenticate(@Pname varchar(50),@categoryname varchar(55))
as
begin
declare @productcount int
declare @categorycount int
set @productcount=(select count(*) from Product where Pname=@Pname )
set @categorycount=(select count(*)from Category where CategoryName=@categoryname)
if(@productcount!=0  @categorycount!=0)
return 1
else
return 0
end

SqlConnection con = new SqlConnection(Constr);
SqlCommand cmd = new SqlCommand("Authenticate",con);
cmd.Parameters.AddWithValue("@Pname", productname);
cmd.Parameters.AddWithValue("@CategoryName", categoryname);
con.Open();
int ctr = (int)cmd.ExecuteScalar();
con.Close();
return ctr;