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: Runtime Error)

s = gets.chomp.split("")#.map(&:to_i)
S = s
MEMO = Array.new(s.size)

ptl = 0

def tree_search(pos)
  return 0 if pos == S.size
  return MEMO[pos] if MEMO[pos]
  min = S.size-1-pos
  a = Array.new(26).map{0}
  for i in 0..(S.size-1-pos)
    a[S[pos+i].ord-97] += 1
    tmp = tree_search(pos+i+1) if a.select{|t| t%2==1}.size == 1
    min = tmp if tmp < min
  end
  return 1 if a.select{|t| t %2 == 1}.size==0
  MEMO[pos] = min+1 
  return min + 1
end

for i in 0..s.size-1
tree_search(i)
end
p tree_search(0)