CF508B.Anton and currency you all know

Berland, 2016. The exchange rate of currency you all know against the burle has increased so much that to simplify the calculations, its fractional part was neglected and the exchange rate is now assumed to be an integer.

Reliable sources have informed the financier Anton of some information about the exchange rate of currency you all know against the burle for tomorrow. Now Anton knows that tomorrow the exchange rate will be an even number, which can be obtained from the present rate by swapping exactly two distinct digits in it. Of all the possible values that meet these conditions, the exchange rate for tomorrow will be the maximum possible. It is guaranteed that today the exchange rate is an odd positive integer n. Help Anton to determine the exchange rate of currency you all know for tomorrow!

伯兰德，2016年。你们所熟知的这种货币对布尔勒（burle）的汇率已大幅上涨，为简化计算，其小数部分被忽略，因此当前汇率被视为一个整数。

可靠消息来源向金融家安东透露了关于该货币对布尔勒明日汇率的一些信息。目前安东已知：明日的汇率将是一个偶数，且该偶数可通过恰好交换今日汇率中的两个不同数字得到。在所有满足上述条件的可能值中，明日的汇率取其中最大的一个。已知今日的汇率是一个奇数正整数 $ n $。请帮助安东确定该货币明日的汇率！

The first line contains an odd positive integer n — the exchange rate of currency you all know for today. The length of number n's representation is within range from 2 to 105, inclusive. The representation of n doesn't contain any leading zeroes.

第一行包含一个正奇数 $n$ —— 即你所熟知的货币今日的汇率。$n$ 的十进制表示长度在 $2$ 到 $10^5$（含）之间。$n$ 的表示中不包含任何前导零。

If the information about tomorrow's exchange rate is inconsistent, that is, there is no integer that meets the condition, print  - 1.

Otherwise, print the exchange rate of currency you all know against the burle for tomorrow. This should be the maximum possible number of those that are even and that are obtained from today's exchange rate by swapping exactly two digits. Exchange rate representation should not contain leading zeroes.

如果关于明日汇率的信息不一致（即不存在满足条件的整数），则输出 -1。

否则，输出大家熟知的货币相对于布尔（burle）的明日汇率。该汇率应为所有满足以下条件的偶数中的最大值：该偶数由今日汇率通过恰好交换两位数字得到。汇率表示中不得包含前导零。