CF934A.A Compatible Pair

Nian is a monster which lives deep in the oceans. Once a year, it shows up on the land, devouring livestock and even people. In order to keep the monster away, people fill their villages with red colour, light, and cracking noise, all of which frighten the monster out of coming.

Little Tommy has n lanterns and Big Banban has m lanterns. Tommy's lanterns have brightness _a_1, _a_2, ..., a__n, and Banban's have brightness _b_1, _b_2, ..., b__m respectively.

Tommy intends to hide one of his lanterns, then Banban picks one of Tommy's non-hidden lanterns and one of his own lanterns to form a pair. The pair's brightness will be the product of the brightness of two lanterns.

Tommy wants to make the product as small as possible, while Banban tries to make it as large as possible.

You are asked to find the brightness of the chosen pair if both of them choose optimally.

年是一种生活在深海中的怪物。每年，它都会登陆陆地，吞噬牲畜甚至人类。为了驱赶这种怪物，人们会在村庄中布满红色、亮光和爆裂声，这些都能吓退年兽。

小汤米有 $n$ 个灯笼，大斑斑有 $m$ 个灯笼。汤米的灯笼亮度分别为 $a_1,\,a_2,\,\dots,\,a_n$，斑斑的灯笼亮度分别为 $b_1,\,b_2,\,\dots,\,b_m$。

汤米打算隐藏自己的一只灯笼；随后，斑斑会从汤米未被隐藏的灯笼中挑选一只，并从自己的灯笼中挑选一只，组成一对。该对灯笼的亮度定义为两只灯笼亮度的乘积。

汤米希望使该乘积尽可能小，而斑斑则希望使其尽可能大。

你需要求出：当双方均采取最优策略时，最终所选配对的亮度值。

The first line contains two space-separated integers n and m (2 ≤ n, m ≤ 50).

The second line contains n space-separated integers _a_1, _a_2, ..., a__n.

The third line contains m space-separated integers _b_1, _b_2, ..., b__m.

All the integers range from  - 109 to 109.

第一行包含两个以空格分隔的整数 $n$ 和 $m$（$2 \leq n, m \leq 50$）。

第二行包含 $n$ 个以空格分隔的整数 $a_1, a_2, ..., a_n$。

第三行包含 $m$ 个以空格分隔的整数 $b_1, b_2, ..., b_m$。

所有整数的取值范围均为 $-10^9$ 到 $10^9$。

Print a single integer — the brightness of the chosen pair.

输出一个整数——所选配对的亮度。

In the first example, Tommy will hide 20 and Banban will choose 18 from Tommy and 14 from himself.

In the second example, Tommy will hide 3 and Banban will choose 2 from Tommy and 1 from himself.

在第一个例子中，Tommy 将隐藏数字 20，而 Banban 将从 Tommy 处选择 18，从自己处选择 14。

在第二个例子中，Tommy 将隐藏数字 3，而 Banban 将从 Tommy 处选择 2，从自己处选择 1。