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#F1777. Anton and currency you all know

    ID: 1783 传统题 2000ms 256MiB 尝试: 0 已通过: 0 难度: 3 上传者: 标签>贪心数学字符串算法思想基础难度共享题库Codeforces英文题面题目来源题面语言

Anton and currency you all know

题目描述

B. Anton and currency you all know
time limit per test
0.5 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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!

Input

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.

Output

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.

Examples
Input
527
Output
572
Input
4573
Output
3574
Input
1357997531
Output
-1

题目来源:fps-www.educg.net-codeforce-1-2833.xml.zip;FPS 共享题包,题包内第 1333 题。保留原作者与原赛事署名。