gets
arr = gets.chomp.split.map(&:to_i)

dp = {}
dp[0] = {}
dp[0][0] = arr[0]
dp[0][1] = arr[0]

def calc_min_and_max(arr, cur)
  r = []
  c = 0
  0.upto(1) do |i|
    r[c] = arr[i] + cur
    c += 1
    r[c] = arr[i] - cur
    c += 1
    r[c] = arr[i] * cur
    c += 1
    r[c] = arr[i] / cur
    c += 1
  end
  [r.max, r.min]
end

1.upto(arr.length - 1) do |i|
  dp[i] = {}
  dp[i] = calc_min_and_max(dp[i - 1], arr[i])
end

p dp
puts dp[arr.size - 1].max