hi all excel gurus....

can some one pls advise me if it possible to identify numbers in pairs
that sum up to become 0?

i have data like

a)-30
b)56
c)30
d)78
e)-90
f)-30
g) -10
h)-9
i) 45
j)10
k)30
L)9
my ans are
as u can see (a) and (C) & (f) and (k) , h&L and g&i

each number can only be used once
can some one help?
thanks