CF1009B.Minimum Ternary String

You are given a ternary string (it is a string which consists only of characters '0', '1' and '2').

You can swap any two adjacent (consecutive) characters '0' and '1' (i.e. replace "01" with "10" or vice versa) or any two adjacent (consecutive) characters '1' and '2' (i.e. replace "12" with "21" or vice versa).

For example, for string "010210" we can perform the following moves:

• "010210" $\rightarrow$ "100210";
• "010210" $\rightarrow$ "001210";
• "010210" $\rightarrow$ "010120";
• "010210" $\rightarrow$ "010201".

Note than you cannot swap "02" $\rightarrow$ "20" and vice versa. You cannot perform any other operations with the given string excluding described above.

You task is to obtain the minimum possible (lexicographically) string by using these swaps arbitrary number of times (possibly, zero).

String $a$ is lexicographically less than string $b$ (if strings $a$ and $b$ have the same length) if there exists some position $i$ ($1 \le i \le |a|$, where $|s|$ is the length of the string $s$) such that for every $j \lt i$ holds $a_j = b_j$, and $a_i \lt b_i$.

给你一个三元字符串（即仅由字符 '0'、'1' 和 '2' 组成的字符串）。

你可以交换任意两个相邻（连续）的字符 '0' 和 '1'（即把 "01" 替换为 "10"，或反之），或者交换任意两个相邻（连续）的字符 '1' 和 '2'（即把 "12" 替换为 "21"，或反之）。

例如，对于字符串 "010210"，我们可以执行以下操作：

• "010210" $\rightarrow$ "100210"；
• "010210" $\rightarrow$ "001210"；
• "010210" $\rightarrow$ "010120"；
• "010210" $\rightarrow$ "010201"。

注意，你不能交换 "02" $\rightarrow$ "20" 或其逆操作。除上述操作外，不允许对给定字符串执行任何其他操作。

你的任务是通过任意次数（可能为零次）的上述交换操作，得到字典序最小的字符串。

若字符串 $a$ 和 $b$ 长度相同，则称字符串 $a$ 字典序小于字符串 $b$，当且仅当存在某个位置 $i$（$1 \le i \le |a|$，其中 $|s|$ 表示字符串 $s$ 的长度），使得对所有 $j \lt i$ 均有 $a_j = b_j$，且 $a_i \lt b_i$。

The first line of the input contains the string $s$ consisting only of characters '0', '1' and '2', its length is between $1$ and $10^5$ (inclusive).

输入的第一行包含一个字符串 $s$，该字符串仅由字符 '0'、'1' 和 '2' 组成，其长度在 $1$ 到 $10^5$（含）之间。

Print a single string — the minimum possible (lexicographically) string you can obtain by using the swaps described above arbitrary number of times (possibly, zero).

输出一个字符串——通过任意次数（可能为零次）执行上述交换操作所能得到的字典序最小的字符串。