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 Ruby (2.3.3) (judge verdict: Accepted)

s = gets.chomp.split('').map{|c| 1<<(c.ord-97)}
N = s.length
hash = Hash.new(10**9)
hash[0] = 0
dp = Array.new(N, 0)
sum = 0
cand = 26.times.map{|i| 1<<i} + [0]
N.times do |i|
    sum ^= s[i]
    dp[i+1] = dp[i] + 1
    cand.each do |c|
        dp[i+1] = hash[sum^c] + 1 if dp[i+1] > hash[sum^c] + 1
    end
    hash[sum] = dp[i+1] if hash[sum] > dp[i+1]
end
puts dp[N]