A palindrome string is a word which reads the same backward as forward, such as or . In this problem we only consider strings with lowercase alphabets.
We newly define the types of palindromes. If a string is not a palindrome, we try to make it a palindrome by removing the minimum number of characters in the string. For a string , if is the minimum number of characters removed to make the string a palindrome, we call the string a type- palindrome. Thus, if is a palindrome, then is a type-0 palindrome.
Given a string , write a program to determine if is a type- palindrome where .
输入格式
Your program is to read from standard input. The input is a single line containing a string with length () of lowercase alphabets.
输出格式
Your program is to write to standard output. Print exactly one line. The line should contain a number among if the input string is a type- palindrome where and otherwise . The negative number means the input string is not a type- palindrome where .
