Evening the Counts

Difficulty: 1000 3000 ms 128 MB

strings

You may append characters to the end of S. Print the minimum number of appends so every character's count becomes even.

Input: one line with a lowercase string.

Output: the number of characters with odd counts.

Constraints:

• 1 ≤ |S| ≤ 10⁵

Sample Tests

aabbc

1

abab

0

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