local mma, mfl = math.max, math.floor
local n = io.read("*n")
local a = {}
for i = 1, n do a[i] = io.read("*n") end
local ret = 0
for i = 1, n do ret = ret + a[i] end

local function rec(v, i)
  if i < n then
    rec(v + a[i], i + 1)
    rec(v - a[i], i + 1)
    rec(v * a[i], i + 1)
  else
    ret = mma(ret, v + a[i])
    ret = mma(ret, v - a[i])
    ret = mma(ret, v * a[i])
  end
end
rec(0, 1)
print(ret)