CF976A.Minimum Binary Number

String can be called correct if it consists of characters "0" and "1" and there are no redundant leading zeroes. Here are some examples: "0", "10", "1001".

You are given a correct string s.

You can perform two different operations on this string:

1. swap any pair of adjacent characters (for example, "101" "110");
2. replace "11" with "1" (for example, "110" "10").

Let val(s) be such a number that s is its binary representation.

Correct string a is less than some other correct string b iff val(a) < val(b).

Your task is to find the minimum correct string that you can obtain from the given one using the operations described above. You can use these operations any number of times in any order (or even use no operations at all).

如果一个字符串仅由字符“0”和“1”组成，且不含多余的前导零，则称其为正确字符串。以下是一些例子：“0”、“10”、“1001”。

给定一个正确字符串 $ s $。

你可以在该字符串上执行以下两种不同的操作：

1. 交换任意一对相邻字符（例如，“101” “110”）；
2. 将子串“11”替换为“1”（例如，“110” “10”）。

令 $ \text{val}(s) $ 表示以 $ s $ 为其二进制表示的数。

若两个正确字符串 $ a $、$ b $ 满足 $ \text{val}(a) < \text{val}(b) $，则称正确字符串 $ a $ 小于正确字符串 $ b $。

你的任务是：通过上述操作（可任意次序、任意次数地使用，也可完全不使用），从给定字符串出发，得到最小的正确字符串。

The first line contains integer number n (1 ≤ n ≤ 100) — the length of string s.

The second line contains the string s consisting of characters "0" and "1". It is guaranteed that the string s is correct.

第一行包含一个整数 $ n $（$ 1 \leq n \leq 100 $）——字符串 $ s $ 的长度。

第二行包含由字符 "0" 和 "1" 组成的字符串 $ s $。保证字符串 $ s $ 是合法的。

Print one string — the minimum correct string that you can obtain from the given one.

输出一个字符串——从给定字符串能得到的字典序最小的合法字符串。

In the first example you can obtain the answer by the following sequence of operations: "1001" "1010" "1100" "100".

In the second example you can't obtain smaller answer no matter what operations you use.

在第一个例子中，你可以通过以下操作序列得到答案：“1001” “1010” “1100” “100”。

在第二个例子中，无论采用何种操作，都无法得到更小的答案。