19422번 - Almost Bobo Number 다국어

문제

A positive integer is called a bobo number if its decimal representation can be obtained by concatenating two copies of the same integer. For example, 12341234ドル$ and 3232ドル$ are bobo numbers, while 1234321ドル$ and 1322ドル$ are not.

A positive integer is called an almost bobo number if, after merging all the consecutive equal digits, the resulting number is a bobo number. For example, $\underbrace{111}\underbrace{222}\underbrace{3}\underbrace{11}\underbrace{22}\underbrace{33}$ becomes 123123ドル$ after merging all the consecutive equal digits, and thus is an almost bobo number.

Bobo has a very large number $n,ドル and he would like to know the largest almomst bobo number less than $n$.

입력

The input contains zero or more test cases, and is terminated by end-of-file. For each test case:

The first line contains an integer $n$ without leading zeros (1ドル \leq n \leq 10^{5,000円,000円}$).

It is guaranteed that the total length of the decimal representations of all $n$ in the input does not exceed 5ドル,000円,000円$.

출력

For each test case, output an integer without leading zeros denoting the largest almomst bobo number strictly less than $n$. If there is no such integer, output $-1$ instead.

제한

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