题目描述

A binary string is a non-empty sequence of $0$'s and $1$'s, e.g., $010110$, $1$, $11101$, etc. The edit distance of two binary strings $S$ and $T$, denoted by $edit(S, T)$, is the minimum number of single-character edit (insert, delete, or substitute) to modify $S$ into $T$. For example, the edit distance of $0011$ and $1100$ is $4$, i.e. $0011 \to 011 \to 11 \to 110 \to 1100$. The edit distance of $1100101$ and $1110100$ is $2$, i.e. $1100101 \to 1110101 \to 1110100$.

Ayu has a binary string $S$. She wants to find a binary string with the same length as $S$ that maximizes the edit distance with $S$. Formally, she wants to find a binary string $T_{max}$ such that $|S| = |T_{max}|$ and $edit(S, T_{max}) \geq edit(S, T')$ for all binary string $T'$ satisfying $|S| = |T'|$.

She needs your help! However, since she wants to make your task easier, you are allowed to return any binary string $T$ with the same length as $S$ such that the edit distance of $S$ and $T$ is more than half the length of $S$. Formally, you must return a binary string $T$ such that $|S| = |T|$ and $edit(S, T) > \frac{|S|}{2}$.

Of course, you can still return $T_{max}$ if you want, since it can be proven that $edit(S, T_{max}) > \frac{|S|}{2}$ for any binary string $S$. This also proves that there exists a solution for any binary string $S$. If there is more than one valid solution, you can output any of them.

输入格式

Input contains a binary string $S$ ($1 \leq |S| \leq 2000$).

输出格式

Output in a line a binary string $T$ with the same length as $S$ that satisfies $edit(S, T) > \frac{|S|}{2}$.

0011

1100

1100101

0011010

提示

Explanation for the sample input/output #1

As illustrated in the example above, the edit distance of $0011$ and $1100$ is $4$. Since $4 > \frac{4}{2}$, $1100$ is one of the valid output for this sample.