Problem:
Score : 700 points

Problem Statement

We have a string s consisting of lowercase English letters.
Snuke is partitioning s into some number of non-empty substrings.
Let the subtrings obtained be s_1, s_2, ..., s_N from left to right. (Here, s = s_1 + s_2 + ... + s_N holds.)
Snuke wants to satisfy the following condition:

For each i (1 \leq i \leq N), it is possible to permute the characters in s_i and obtain a palindrome.

Find the minimum possible value of N when the partition satisfies the condition.

Constraints

1 \leq |s| \leq 2 \times 10^5

s consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

s

Output

Print the minimum possible value of N when the partition satisfies the condition.

Sample Input 1

aabxyyzz

Sample Output 1

2

The solution is to partition s as aabxyyzz = aab + xyyzz.
Here, aab can be permuted to form a palindrome aba, and xyyzz can be permuted to form a palindrome zyxyz.

Sample Input 2

byebye

Sample Output 2

1

byebye can be permuted to form a palindrome byeeyb.

Sample Input 3

abcdefghijklmnopqrstuvwxyz

Sample Output 3

26

Sample Input 4

abcabcxabcx

Sample Output 4

3

The solution is to partition s as abcabcxabcx = a + b + cabcxabcx.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Scanner;
import java.util.Stack;

class Main {

    public static void main(String[] args) {
        new Main().compute();
    }

    void compute() {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int[] imos = new int[s.length() + 1];
        for (int i = 1; i < s.length() + 1; i++) {
            imos[i] = imos[i - 1] ^ 1 << s.charAt(i - 1) - 'a';
        }
        int[] kaibuns = new int[27];
        for (int i = 0; i < 26; i++) {
            kaibuns[i + 1] = 1 << i;
        }
        int[] dp = new int[1 << 26];
        Arrays.fill(dp, 1 << 26);
        dp[0] = 0;
        for (int i = 1; i < s.length() + 1; i++) {
            int min = 1 << 26;
            for (int j = 0; j < 27; j++) {
                min = Math.min(min, dp[imos[i] ^ kaibuns[j]] + 1);
            }
            dp[imos[i]] = Math.min(min, dp[imos[i]]);
        }
        System.out.println(dp[imos[s.length()]]);
    }
}