Codeforces Round 342 (Div. 2)
D
Finals in arithmetic
Codeforces
2400
原题
← CE →
翻译中…

Vitya is studying in the third grade. During the last math lesson all the pupils wrote on arithmetic quiz. Vitya is a clever boy, so he managed to finish all the tasks pretty fast and Oksana Fillipovna gave him a new one, that is much harder.

翻译中…

Let's denote a flip operation of an integer as follows: number is considered in decimal notation and then reverted. If there are any leading zeroes afterwards, they are thrown away. For example, if we flip $123$ the result is the integer $321$, but flipping $130$ we obtain $31$, and by flipping $31$ we come to $13$.

翻译中…

Oksana Fillipovna picked some number $*a*$ without leading zeroes, and flipped it to get number $*a*_{*r*}$. Then she summed $*a*$ and $*a*_{*r*}$, and told Vitya the resulting value $*n*$. His goal is to find any valid $*a*$.

翻译中…

As Oksana Fillipovna picked some small integers as $*a*$ and $*a*_{*r*}$, Vitya managed to find the answer pretty fast and became interested in finding some general algorithm to deal with this problem. Now, he wants you to write the program that for given $*n*$ finds any $*a*$ without leading zeroes, such that $*a* + *a*_{*r*} = *n*$ or determine that such $*a*$ doesn't exist.

翻译中…

Input

翻译中…

The first line of the input contains a single integer $*n*$ ($1 ≤ *n* ≤ 10^{100 000}$).

翻译中…

Output

翻译中…

If there is no such positive integer $*a*$ without leading zeroes that $*a* + *a*_{*r*} = *n*$ then print $0$. Otherwise, print any valid $*a*$. If there are many possible answers, you are allowed to pick any.

翻译中…

Note

翻译中…

In the first sample $4 = 2 + 2$, $*a* = 2$ is the only possibility.

翻译中…

In the second sample $11 = 10 + 1$, $*a* = 10$ — the only valid solution. Note, that $*a* = 01$ is incorrect, because $*a*$ can't have leading zeroes.

翻译中…

It's easy to check that there is no suitable $*a*$ in the third sample.

翻译中…

In the fourth sample $33 = 30 + 3 = 12 + 21$, so there are three possibilities for $*a*$: $*a* = 30$, $*a* = 12$, $*a* = 21$. Any of these is considered to be correct answer.

翻译中…

样例

Input #1
4
Output #1
2
InputCopy OutputCopy
Input #2
11
Output #2
10
InputCopy OutputCopy
Input #3
5
Output #3
0
InputCopy OutputCopy
Input #4
33
Output #4
21
InputCopy OutputCopy
题目信息
题号
625D
时间限制
2 s
内存限制
256 MB
标签
构造
模拟
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。