CF614B.Gena's Code

It's the year 4527 and the tanks game that we all know and love still exists. There also exists Great Gena's code, written in 2016. The problem this code solves is: given the number of tanks that go into the battle from each country, find their product. If it is turns to be too large, then the servers might have not enough time to assign tanks into teams and the whole game will collapse!

There are exactly n distinct countries in the world and the i-th country added a__i tanks to the game. As the developers of the game are perfectionists, the number of tanks from each country is beautiful. A beautiful number, according to the developers, is such number that its decimal representation consists only of digits '1' and '0', moreover it contains at most one digit '1'. However, due to complaints from players, some number of tanks of one country was removed from the game, hence the number of tanks of this country may not remain beautiful.

Your task is to write the program that solves exactly the same problem in order to verify Gena's code correctness. Just in case.

现在是公元 4527 年，我们熟悉并喜爱的坦克游戏依然存在。同时，伟大的格纳（Great Gena）于 2016 年编写的代码也依然存在。该代码解决的问题是：给定每个国家投入战斗的坦克数量，求它们的乘积。如果该乘积过大，则服务器可能没有足够的时间将坦克分配到各支队伍中，从而导致整个游戏崩溃！

世界上恰好有 $n$ 个互不相同的国家，其中第 $i$ 个国家向游戏中加入了 $a_i$ 辆坦克。由于游戏开发者是完美主义者，每个国家的坦克数量均为“优美的数”。根据开发者的定义，“优美的数”是指其十进制表示仅由数字 '1' 和 '0' 组成，且至多包含一个数字 '1'。然而，由于玩家投诉，某个国家的一部分坦克被从游戏中移除了，因此该国家的坦克数量可能不再保持“优美”。

你的任务是编写一个程序，解决完全相同的问题，以验证格纳代码的正确性（以防万一）。

The first line of the input contains the number of countries n (1 ≤ n ≤ 100 000). The second line contains n non-negative integers a__i without leading zeroes — the number of tanks of the i-th country.

It is guaranteed that the second line contains at least n - 1 beautiful numbers and the total length of all these number's representations doesn't exceed 100 000.

输入的第一行包含国家数量 $n$（$1 \leq n \leq 100\,000$）。第二行包含 $n$ 个非负整数 $a_i$（无前导零）——第 $i$ 个国家的坦克数量。

保证第二行中至少包含 $n-1$ 个“优美数”，且所有这些数的十进制表示的总长度不超过 $100\,000$。

Print a single number without leading zeroes — the product of the number of tanks presented by each country.

输出一个不含前导零的数字——即每个国家所展示的坦克数量的乘积。

In sample 1 numbers 10 and 1 are beautiful, number 5 is not not.

In sample 2 number 11 is not beautiful (contains two '1's), all others are beautiful.

In sample 3 number 3 is not beautiful, all others are beautiful.

在样例 1 中，数字 10 和 1 是美丽的，数字 5 不是美丽的。

在样例 2 中，数字 11 不是美丽的（包含两个字符 '1'），其余所有数字都是美丽的。

在样例 3 中，数字 3 不是美丽的，其余所有数字都是美丽的。