def div(a, b)
  if b.zero?
    nil
  elsif a.positive?
    a / b
  else
    - (-a / b)
  end
end

n = gets.to_i
xs = gets.chomp.split.map(&:to_i)
mn = xs[0]
mx = xs[0]
(1...n).each do |i|
  x = xs[i]
  ys = []
  ys << mn + x
  ys << mn - x
  ys << mn * x
  ys << mx + x
  ys << mx - x
  ys << mx * x
  r = div(mx, x)
  ys << r if r
  r = div(mn, x)
  ys << r if r
  mn = ys.min
  mx = ys.max
end

p mx