SUM - Somar resultado de dois sum

Olá meus amigos(as), preciso somar o resultado do (sum(ss.qtde * i.vlrmed) saida,) com (sum(ss.qtde * i.vlrmed) saida,), alguém me ajude por favor.


select
data,
doc,
grupo,
cdc,
cod,
matmed,
und,
saida_qtde,
cast(custo as numeric (10,2))custo,
cast(saida as numeric (10,2)) saida,
devol_qtde,
cast(devol as numeric (10,2)) devol
from (
select
s.data,
s.doc,
'SAIDA' movimentacao,
(select first 1 g.nome from gegrupos g where g.cod = i.gru) grupo,
(select first 1 nome from tbcencus where cod=s.cdc) cdc,
ss.item cod,
i.nome matmed,
i.uni_con und,
sum(qtde)saida_qtde,
cast(i.vlrmed as numeric (10,2))custo,
sum(ss.qtde * i.vlrmed) saida,
0 devol_qtde,
0 devol
from gecadsai s
left join gelansai ss on s.ano=ss.ano and s.mes=ss.mes and s.doc=ss.doc
left join geitens i on ss.item=i.cod
where ss.consol='T'
and s.data between :data1 and :data2
group by
s.data,
s.doc,
i.gru,
s.cdc,
ss.item,
i.nome,
i.uni_con,
s.data,
i.vlrmed,
ss.qtde

UNION

select
d.data,
d.doc,
'DEVOLUÇÃO' movimentacao,
(select first 1 g.nome from gegrupos g where g.cod = ii.gru) grupo,
(select max(nome) from tbcencus where cod=d.cdc) cdc,
l.item cod,
ii.nome matmed,
ii.uni_con und,
0 saida,
0 saida_qtde,
sum(qtde)devol_qtde,
cast(ii.vlrmed as numeric (10,2))custo,
sum(l.qtde * ii.vlrmed) devol
from gecaddev d
left join gelandev l on d.id=l.id_gecaddev
left join geitens ii on l.item=ii.cod
where l.consol='T'
and d.data between :data1 and :data2
group by
d.data,
d.doc,
ii.gru,
d.cdc,
l.item,
ii.nome,
ii.uni_con,
d.data,
ii.vlrmed,
l.qtde
)
order
by cdc,
matmed,
cod