SQL Error: Conversion failed when converting the nvarchar value to data type int.

hi every in this respected forum

how can in sql server show two columns as one column.. one of them is nvarchar  and the other is int from two tables i have did this but it give error

select depart.depart_name+input_comp.no_of_depart as department,dbo.depart.depart_id  from dbo.depart inner join dbo.input_comp  on dbo.depart.depart_id=dbo.input_comp.depart_id group by depart.depart_name,dbo.depart.depart_id,input_comp.no_of_depart

the depart_name is nvarchar datatype and the no_of_depart is int datatype

the error is

Conversion failed when converting the nvarchar value to data type int.   any help will appreciated