f = Const("f")
a = Const("a")
b = Const("b")
nodes = {}
function mk_big(num)
local r
if num == 0 then
r = f(a, b)
else
r = f(mk_big(num-1), mk_big(num-1))
end
return r
function size(e)
local r = 0
e:for_each(function(e, o) assert(e:is_app() or e:is_constant()); r = r + 1 end)
local F = mk_big(14)
print(size(F))