Longest Palindrome Length

You are given a string s consisting of lower-case English letters. Your task is to determine the length of the longest palindrome that can be formed using the letters from s.

A palindrome is a string that reads the same forwards and backwards. You can rearrange the letters in any order to form the palindrome. For example, if the input string is abccccdd, one of the longest palindromes that can be constructed is dccaccd, which has a length of 7.

Note: If there is at least one character with an odd frequency, you can place exactly one of such characters in the middle of the palindrome.

inputFormat

The input consists of a single line containing the string s with at most 10,000 characters.

outputFormat

Output a single integer representing the length of the longest palindrome that can be formed.

a

1